Klay versus Wilt?
Wilt Chamberlain routinely posted incredible scoring totals during the 1960's. For instance, he scored 50+ points in a single game a staggering 118 times in his career, including 45 times in the 1961-62 season alone. By comparison, next on the career list are Michael Jordan with 31 such games, and then Kobe Bryant with 25.
In fact, Chamberlain himself provided almost a quarter of all the 50-point games across more than seven decades of NBA history (Klay Thompson's recent 52-point game against Chicago was the 487th time this feat has been accomplished). It wasn't until the 1980's that the rest of the NBA (combined!) caught up to Chamberlain - Bernard King scoring 50 in a losing cause for the Warriors in 1981 against the 76ers, marked the 118th time that someone not named Chamberlain had scored 50+ points in a single game.
It's true that it's not quite fair to compare games from the three-pointer era against older games. On the other hand, it's also not quite fair to compare a 48-minute performance by Chamberlain (who rarely went to the bench, and never fouled out in his entire career) against a performance by a modern player who tops 50 points in three quarters and then sits out the entire 4th quarter of a blowout.
So another simple way to look at this is to calculate points-per-minute, or to put it more into Wilt terms, "points per 48 minutes". Of course, anyone can come into the final minute of garbage time and make a three-pointer and get a ridiculous score by this measure, so let's restrict ourselves to just the games where a player scored at least 35 points. By this measure (points per 48 minutes), has anyone ever topped Wilt's most famous game where he scored 100 points in 48 minutes?
Not quite. Here are the top ten single-game performances when you sort by "points per 48 minutes (PP48M)":
#1 100.0 PP48M, Wilt Chamberlain: 100 points in 48:00 minutes (3/2/1962 PHW vs NYK)
#2 99.14 PP48M, Klay Thompson: 60 points in 29:03 minutes (12/5/2016 GSW vs IND)
#3 94.01 PP48M, Klay Thompson: 52 points in 26:33 minutes (10/29/2018 GSW vs CHI)
#4 92.72 PP48M, Kobe Bryant: 81 points in 41:56 minutes (1/22/2006 LAL vs TOR)
#5 90.50 PP48M, Kobe Bryant: 62 points in 32:53 minutes (12/20/2005 LAL vs DAL)
#6 88.72 PP48M, Karl Malone: 61 points in 33:00 minutes (1/27/1990 UTA vs MIL)
#7 86.85 PP48M, Quintin Dailey: 38 points in 21:00 minutes (1/28/1986 CHI vs NYK)
#8 86.40 PP48M, Kiki Vandeweghe: 36 points in 20:00 minutes (4/15/1988 POR vs GSW)
#9 82.00 PP48M, CJ McCollum: 50 points in 29:16 minutes (1/31/2018 POR vs CHI)
#10 81.40 PP48M, Damian Lillard: 50 points in 29:29 minutes (2/9/2018 POR vs SAC)
So by this measure, Klay Thompson now has two of the three all-time best single-game performances, topping even Kobe Bryant's two famous outbursts where he scored 81 points against Toronto and when he scored 62 points in three quarters against Dallas.
This calculation is a bit unreliable, because minutes played are not available for all games in NBA history, so it's somewhat skewed toward the present day, and also if you go far back enough, only integer minutes played are available, rather than precise minutes and seconds. You can see that in the above top-ten list, where the games from Karl Malone, Quintin Dailey (!), and Kiki Vandeweghe don't have the exact seconds available.
Interestingly enough, Wilt Chamberlain doesn't show up again on this list until #39 and #40, since his next-best performances in games that didn't go into overtime were scoring a mere 73 points while playing all 48 minutes, in a couple of games from 1962. He almost always played the whole game. Out of the 118 games where Chamberlain scored 50+ points, there were 3 games where minutes played are not available, 15 overtime games, 2 games where he played 43 minutes, 3 games where he played 45 minutes, 9 games where he played 47 minutes, and 86 games where he played 48 minutes!
Here is the rest of the top-40. You might also notice #23 Stephen Curry's career best "points per 48 minutes" from last week against Washington. Also note that I didn't manage to look up precise seconds for these games, so the rankings might shift around a bit if those were included:
#11 81.4 PP48M, David Thompson: 73 points in 43 minutes (4/9/1978 DEN vs DET)
#12 80.0 PP48M, Sleepy Floyd: 40 points in 24 minutes (2/26/1991 HOU vs DEN)
#13 79.1 PP48M, Kobe Bryant: 61 points in 37 minutes (2/2/2009 LAL vs NYK)
#14 79.0 PP48M, Kobe Bryant: 56 points in 34 minutes (1/14/2002 LAL vs MEM)
#15 78.9 PP48M, Kobe Bryant: 51 points in 31 minutes (2/12/2003 LAL vs DEN)
#16 78.9 PP48M, Damian Lillard: 51 points in 31 minutes (2/19/2016 POR vs GSW)
#17 78.8 PP48M, Kemba Walker: 46 points in 28 minutes (3/22/2018 CHO vs MEM)
#18 77.5 PP48M, Jerry West: 63 points in 39 minutes (1/17/1962 LAL vs NYK)
#19 77.4 PP48M, David Robinson: 71 points in 44 minutes (4/24/1994 SAS vs LAC)
#20 77.3 PP48M, Russell Westbrook: 58 points in 36 minutes (3/7/2017 OKC vs POR)
#21 77.0 PP48M, Larry Bird: 53 points in 33 minutes (3/30/1983 BOS vs IND)
#22 76.8 PP48M, James Harden: 56 points in 35 minutes (11/5/2017 HOU vs UTA)
#23 76.5 PP48M, Stephen Curry: 51 points in 32 minutes (10/24/2018 GSW vs WAS)
#24 76.3 PP48M, Carmelo Anthony: 62 points in 39 minutes (1/24/2014 NYK vs CHA)
#25 75.9 PP48M, Pete Maravich: 68 points in 43 minutes (2/25/1977 NOJ vs NYK)
#26 75.7 PP48M, Elgin Baylor: 71 points in 45 minutes (11/15/1960 LAL vs NYK)
#27 75.6 PP48M, Patrick Ewing: 41 points in 26 minutes (4/13/1988 NYK vs IND)
#28 75.6 PP48M, Tracy McGrady: 52 points in 33 minutes (2/21/2003 ORL vs CHI)
#29 75.6 PP48M, Klay Thompson: 52 points in 33 minutes (1/23/2015 GSW vs SAC)
#30 75.2 PP48M, Michael Jordan: 58 points in 37 minutes (2/26/1987 CHI vs NJN)
#31 75.1 PP48M, Mark Aguirre: 36 points in 23 minutes (1/29/1987 DAL vs DEN)
#32 74.6 PP48M, Devin Booker: 70 points in 45 minutes (3/24/2017 PHO vs BOS)
#33 74.6 PP48M, George Gervin: 42 points in 27 minutes (11/10/1984 SAS vs CLE)
#34 73.6 PP48M, Gilbert Arenas: 46 points in 30 minutes (2/25/2006 WAS vs NYK)
#35 73.6 PP48M, Stephen Curry: 46 points in 30 minutes (4/13/2016 GSW vs MEM)
#36 73.4 PP48M, Kobe Bryant: 52 points in 34 minutes (11/30/2006 LAL vs UTA)
#37 73.3 PP48M, Jermaine O'Neal: 55 points in 36 minutes (1/4/2005 IND vs MIL)
#38 73.0 PP48M, Ben Gordon: 35 points in 23 minutes (3/30/2005 CHI vs CHA)
#39 73.0 PP48M, Wilt Chamberlain: 73 points in 48 minutes (11/16/1962 SFW vs NYK)
#40 73.0 PP48M, Wilt Chamberlain: 73 points in 48 minutes (1/13/1962 PHW vs CHP)
And if we count up the career number of games with 60+ points per 48 minutes, Wilt Chamberlain is still at the top of the list, but only just barely:
#1 Wilt Chamberlain (30)
#2 Michael Jordan (28)
#3 Stephen Curry (17)
#4 Kobe Bryant (16)
#5 James Harden (15)
#6 George Gervin (11)
#7 Dominique Wilkins (10)
#7 Russell Westbrook (10)
#9 Rick Barry (7)
#9 Shaquille O'Neal (7)
#11 Klay Thompson (6)
#11 Larry Bird (6)
#11 Tracy McGrady (6)
#14 Bernard King (5)
#14 Damian Lillard (5)
#14 LeBron James (5)
#14 Mark Aguirre (5)
We could also do this as a pace-adjusted calculation, to see who scored the most points per possession in a single game - has anyone ever done this?