I did a brief look at where teams who won (and lost) the World Series finished in the regular season, and chose to expand upon that study. Instead of just looking at where the teams finished in their individual season, I wanted to see how the teams performed over a five year window. So I expanded the study to include the two years prior to and after the team won the pennant. I examined the team based on the total number of wins earned that year and where that team finished in total wins for that season. Here's what I found:
The 1995 Braves may be the strongest team in terms of overall success to win the World Series. Overall they averaged an obscene 1.2 in the NL over the 5 year window (1993-1997), and averaged nearly 95 wins a season over that period. They, of course, won the NL Pennant in 1996, and lost to the Yankees. This is in spite of two shortened seasons which drags down their overall number.
The Indians were no slouches themselves. The poor 1993 season drags down their overall win placement, but the Indians ranked an overall solid 3.6 in win finish.
Yankees: 90.6 Wins, 1.6 Avg. Finish
Braves: 95 Wins, 1.2 Avg. Finish
'96 displayed arguably the two best teams of the decade. The Yankees (as I'm sure we all recall) won three titles in the '90s. However, the Braves actually outperform the Yankees in terms of wins and win ranking for their league. This is the only matchup of two teams which nearly averaged finishing first in their league in wins over a 5 year period. The only other franchise to average better than 2nd place in their league (and make/win a World Series) is the Philadelphia Phillies who averaged a slightly better than 2nd place finish from 2008-2012.
Marlins: 71.4 Wins, 10.4 Avg. Finish
Indians: 94.4 Wins, 2.2 Avg. Finish
If you want to argue the playoffs are a crapshoot, and where you finish doesn't matter, look no further than the 1997 Marlins. No weaker franchise has ever won the World Series over this period. The Marlins are the only World Series team to average under 81 wins over a five year period, and it's not close. Surprisingly, the next closest franchise period is the 2013 Boston Red Sox; the Red Sox averaged 81 wins from 2011-2015. This is also the biggest discrepancy from a team which won the World Series over a team which lost.
Yankees: 97.8 Wins, 2 Avg. Finish
Padres: 83 Wins, 7.4 Avg. Finish
The Padres are reminiscent of the kind of moderate flukes you see from time to time in pennant/World Series winners. The Padres were a fine club from 1996-2000. They averaged a little over 81 wins over the period, they made the playoffs twice, and won their division once. Overall, a solid time to be a Padres fan (especially with Hall of Famer Tony Gwynn spraying hits all over the field). They could not overcome the Yankees unfortunately.
Yankees: 98.4 Wins, 2.2 Avg. Finish
Braves: 98.6 Wins, 2 Avg. Finish
The second battle of the '90s titans, they both had cooled off at this point.
Yankees: 99.4 Wins, 2.2 Avg. Finish
Mets: 87.2 Wins, 6.7 Avg. Finish
It still stuns me the Yankees attended four World Series in a row, and 6 of 8 World Series from 1996-2003. The Mets were a solid franchise, and snuck in around the Braves and Giants that year. Despite finishing 4th in wins in the NL: they were only three wins behind the NL leading Giants.
Diamondbacks: 91.8 Wins, 4.4 Avg. Finish
Yankees: 96.8 Wins, 2.4 Avg. Finish
The Diamonbacks were a great franchise when they first came out. They aggressively signed Randy Johnson & Reggie Sanders, traded for Curt Schilling, Luis Gonzalez; and it all worked out. 2001 was not their best season (that was 1999), but it was up there for them. The Yankees were the Yankees.
Angels: 85.8 Wins, 6 Avg. Finish
Giants: 94.6 Wins, 3 Avg. Finish
The Giants would make up for their moderately poor luck in the early 2000s with amazing luck in the early part of the '10s. They finally made the World Series only to get eliminated from the upstart Anaheim Angels. Incidentally the 2002 Angels are one of the few teams to win a World Series without benefiting from a Hall of Famers' performance. Ironically for the Angels, they'd actually start playing much better later in the decade (including a 100 win season in 2008) but came up empty.
Marlins: 82.4 Wins, 7.2 Avg. Finish
Yankees: 99 Wins, 1.8 Avg. Finish
The Marlins remain one of two franchises to never win their division (the other being the Colorado Rockies); and yet they've won two World Series (more than 10 other franchises, all but the Rays older). However, their 2003 win was far less flukey than their 1997 one. The Marlins weren't a terrible team after their 2003 win; they collapsed after their '97 title.
2003 was the end of the 'good' times for the Yankees. They return a little later, but compared to their '90s peak they've fallen off, although not due to a lack of success as we can see.
Red Sox: 93.4 Wins, 3.4 Avg. Finish
Cardinals: 94 Wins, 3.4 Avg. Finish
Few matchups featured two more evenly matched teams in terms of wins and average finish. 2004 represents the start of a great two decades for both the Cardinals and the Red Sox. The Cardinals have been more consistent, and appeared in more World Series overall, but the Red Sox have won four titles since 2000. Overall, this broke one of baseball's more infamous losing streaks. The Red Sox were a good franchise too; with the Yankees largely keeping them in check.
2005 is the tale of two mediocre franchises getting lucky. The White Sox were legit in 2005 (they led the AL in wins after all) but were a pretty poorly ran franchise. They didn't make the playoffs any other time in their window, and only two other times that decade (and once since). The Astros were mildly better, but were contained by the Cardinals. They would start losing, badly, before moving to the AL.
Cardinals: 90.4 Wins, 4.4 Avg. Finish
Tigers: 80 Wins, 8 Avg. Finish
This is a pretty fluky pennant win by the Tigers, but not for the Cards. Ironically, the Cardinals worst team to make the playoffs in years was the one to break through and win the World Series. If you want to argue for the playoffs being a crapshoot: the 2006 Cardinals are your Exhibit A. They were a middling team (they only won 83 games, lowest in the sample), but the Cardinals are well run and came off two straight 100 win seasons.
The Tigers have won as much as any other team in the AL Central, they've gotten little to show for it. Two pennants, but two sweeps. I've mentioned this before, but the two worst ran franchises in our division have won the only titles since the playoffs expanded. Thankfully (for Detroit) their string of good play would continue for nearly a decade.
Red Sox: 93.4 Wins, 3.2 Avg. Finish
Rockies: 79.8 Wins, 8.2 Avg. Finish
The Rockies also came up with a pretty fluky pennant in 2007, although perhaps people underestimate them. They did lead the league in wins for the NL (tied with the way over-performing Arizona Diamondbacks). Then again they did get clobbered by the Red Sox, who edged out the Indians to make the World Series (who, coincidentally, only had an 82.6 average number of wins from 2005-2009).
Phillies: 91.2 Wins, 2.4 Avg. Finish
Rays: 80.8 Wins, 8 Avg. Finish
The Rays first winning season turned into a pennant. David Price broke out, as did Evan Longoria. They defeated the dreaded Red Sox to reach the World Series, but ran into the excellent Phillies who redeemed a poor showing in the 2007 playoffs to win the whole thing. The Phillies fielded better teams, including a great rotation with Roy Halladay, Cliff Lee, Cole Hamels and Roy Oswalt, but failed to win another title.
Yankees: 95.6 Wins, 2.2 Avg. Finish
Phillies: 94.6 Wins, 1.8 Avg. Finish
If you want to argue money wins titles the 2009 Yankees are your Exhibit A. The Yankees already had Alex Rodriguez and Derek Jeter, but also paid to bring in C.C. Sabathia and Mark Texiera. It paid off after missing the playoffs in 2008, and they won 103 games, defeated the NL Champs, and claimed a ring. Thankfully they have not returned to the World Series since.
Giants: 94 Wins, 3 Avg. Finish
Rangers: 89 Wins, 4.6 Avg. Finish
Both the Rangers and the Giants were solid teams throughout this period, the Rangers failed to quite win the World Series, but the Giants created even year magic for the first half of the '10s.
Cardinals: 90.4 Wins, 4 Avg. Finish
Rangers: 91.4 Wins, 3 Avg. Finish
The Rangers got screwed, and the Cardinals claimed their second ring of the sample.
Giants: 87.2 Wins, 4.4 Avg. Finish
Tigers: 89.4 Wins, 4 Avg. Finish
The Tigers could never quite break through except for 2012. It was their worst team of the sample, and they got swept. The Tigers paid a heavy price, but consistently good teams just didn't work for Detroit. They would slowly collapse and now are basement dwellers. The 2012 Tigers team was pretty fluky, but their string of success is in line with the sample.
Red Sox: 81 Wins, 8 Avg. Finish
Cardinals: 93 Wins, 2.8 Avg. Finish
The Red Sox have taken the most advantage of their winning years of any team in baseball, and then paid the highest price afterwards. The 2013 string shows why: this was the only year the Red Sox even made the playoffs in the 5 year sample, and they of course won the whole thing. The Cardinals were at their peak in terms of success as a franchise in the sample.
Giants: 85.8 Wins, 4.8 Avg. Finish
Royals: 79.6 Wins, 7.4 Avg. Finish
The 2015 Royals were a great team. Their franchise? Not so much. 3 winning seasons since 1995, and they have two pennants and a ring to show for it. As a franchise: this pennant is fluky. 2015 is kinda in line.
Royals: 86.2 Wins, 5.6 Avg. Finish
Mets: 79.6 Wins, 7.4 Avg. Finish
The Mets are a strange and sad franchise, they can never seem to pull it all together. I was at the game where the Mets lost it all. They should have left in Matt Harvey. A side note: the 2015 Royals also lack a clear Hall of Famer.
Cubs: 92 Wins, 4.4 Avg. Finish
Indians: 90.6 Wins, 4.4 Avg. Finish
The less said here the better, I suppose...the Cubs were in line with other winners, but not the dynasty predicted at the time. Cleveland started a three year hot streak.
Astros: 96.2 Wins, 3.2 Avg. Finish*
Dodgers: 96.8 Wins, 2.6 Avg. Finish
If it weren't for the fact the Dodgers are from LA I'd feel bad for them. They've been an amazing franchise the past several years, and just can't get a ring. The Astro's cheated, so instead of praising their strategy of tanking I'll leave the asterisk.
The data set can be found below. Overall I don't think the playoffs are quite as big of a crapshoot as people like to think. Overall it seems really good teams, and especially teams with prolonged success, win the whole thing.