Is the American Summer Olympic dynasty crumbling?

A creeping concern is growing in Tokyo where Team USA’s stranglehold on the Summer Olympics is under threat.

Some high achievers like the U.S. women’s gymnastics team — winners of the previous four major international meets — have fallen to earth. The American women settled for a silver medal Tuesday amid the chaos of superstar Simone Biles stepping off the Olympic stage because of the mental strain of living up to the gold standard foisted upon her.

The U.S. softball team, which once crushed rivals, also lost on Tuesday, falling to host Japan 2-0 in the gold medal game, while the top-ranked women’s soccer team barely advanced to the knockout round after an underwhelming scoreless draw against Australia.

Then there was the men’s basketball team’s 83-76 opening-game defeat to France last weekend — the Americans’ first Olympic setback in men’s hoops since 2004.

Entering competition Tuesday night the United States had the most overall medals with 25 but was one behind Japan in gold medals — 10 to 9. So far, it has failed to meet its gold standard in events it usually dominates.

The shaky first week raises begs the question: Is this the death of American sports supremacy as we know it?

“People get older and dynasties crumble,” Olympic historian Bill Malon said Tuesday from Tokyo. “The Roman Empire went away.”

In other words, nothing lasts forever. Not even when talking about one of the greatest athletes in our lifetime like Biles.

She astonishingly tumbled from her perch after the weight of expectation in the pre-Olympic buildup became too much to handle.

After winning four gold medals at the Rio Games in 2016, Biles told reporters on Tuesday that her love of gymnastics had been stripped from her.

“This Olympic Games, I wanted it to be for myself,” Biles said. “I was still doing it for other people, so it hurts my heart that doing what I love has been kind of taken away from me to please other people.”

Lost in the hoopla is that Biles, 24, is one of the hundreds of victims of Larry Nassar, the Michigan State and USA Gymnastics team physician who is serving a prison sentence for molesting women and girls.

While training for the Tokyo Games, Biles has criticized sports officials, including those from the U.S. Olympic & Paralympic Committee, for not doing enough to prevent future episodes of sexual abuse.

The reigning world champion soccer team, like Biles, came to Tokyo with expectations of greatness. But the United States opened the tournament with a 3-0 thrashing by Sweden and, honestly, was outplayed by Australia on Tuesday.

“The one thing that surprised me a little bit was that they were a bit passive in their pressing, and I’m used to seeing them very, very aggressive,” Australia coach Tony Gustavsson said in a news conference.

That will have to change when the U.S. plays the Netherlands on Friday morning in a quarterfinal showdown featuring the 2019 World Cup finalists. The United States won that game 2-0.

It is going for its fifth gold medal and trying to become the first country to win the World Cup and Olympics back-to-back.

But the United States failed to medal for the first time in the Olympics in 2016 when nemesis Sweden eliminated the Americans in the quarterfinals in Brazil.

Bob Condron, a former USOPC executive who attended 16 Olympics, is optimistic about the coming days.

“There are always going to be some disappointments,” he said Tuesday. “But at the end of the rodeo the U.S. is best. The Olympics are our shining moment.”

The Tokyo Games end Aug. 8 so the final chapter still needs to be written. But anyone paying attention can see the direction the normally dominant Team USA is headed after a few days of head-scratching performances.

Not that this is the first time results have led to concern. When an all-star college team led by David Robinson won “only” a bronze medal at the 1988 Seoul Games, USA Basketball officials had enough of the pretense.

They presented the world with the original Dream Team of NBA stars four years later in Barcelona.

The latest version of NBA stars has lost its sense of invincibility as France showed over the weekend. U.S. coach Gregg Popovich highlighted the point by reminding reporters that the NBA is a global game now.

“That’s a little bit of hubris if you think that America should just roll the ball out and win,” he said.

The changing outlook might be bad for American Olympians, but it is good for the Olympics. What many seem to forget, competition makes sports worth watching.

As much as we have marveled at Stanford swimmer Katie Ledecky winning races by half a length, she sucked the drama from the pool by her dominance at the 2012 and 2016 Games.

So imagine the suspense the other day in watching an older Ledecky give everything she had against Australia’s Ariarne Titmus in the 400-meters freestyle.

Ledecky, 24, finished with her fastest time in five years — 3 minutes 57.36 seconds — but she lost.

Ledecky could not have shown more joy over the silver-medal swim because she gets it. It’s about giving the best performance wherever that might fall.

Triumph against the odds provides the riveting experience to keep Olympic audiences returning. If not for those heart-tugging moments the 17-day sports showpiece would have been as stale as day-old bread a long time ago.

Without the Miracle on Ice and Boys on the Boat, the Games might never have become the billion-dollar engine it is in 2021.

“There is nothing broken about it,” said Harvey Schiller, former executive director of the U.S. Olympic & Paralympic Committee. “No one told the other side they were supposed to lose.”