Is track the only sport where “Pros” routinely get beat by high schoolers or college age kids?

Well, it's one of the very few sports where that's a possibility. I don't follow swimming enough, but I assume they host "open" meets like they do in track, probably not quite as often I'd guess. How is a college football player supposed to play an NFL player? It just doesn't happen. I'd guess that it can happen in any individual sport. Teams sports, the logistics won't ever work out.

What about:

Gymnastics

Figure skating

Basketball (when a kid turns pro out of high school or before his collegiate eligibility is up?

Football (when they leave college early to go pro

Baseball has a lot of high schoolers skipping college and going pro

Tennis

There are probably others.

So I guess the answer to your question is no.

All those sports are technical, compared to running (an early childhood skill).

Even swimming, you have to learn how to turn.

Swimming! I knew there was a major sport I was forgetting.

Soccer also qualifies- out of high school pros are fairly common.

Also golf and all "extreme" sports like skateboarding and snowboarding.

The reason a lot of younger athletes don't beat pros in team sports is because in team sports you can sandbag and let other players carry you to victory.

If the best college basketball team played an NBA team, there would be 10+ players on the NBA team who get outscored by multiple players from the college team. I would say that statistically, you could make a good argument that those NBA players would be outclassed by the college kids.

This isn't sarcasm- I don't understand what your statement has to do with the question.

It's not uncommon for high schoolers and college athletes to compete with pros in many sports.

Also, swimming, sometimes in soccer, hockey, chess isn't really a sport but it happens there, darts, wasn't there some good kid in cornhole, golf generally gets a few amateurs beating pros, most of the 'extreme' sports like skateboarding/snowboard etc

I'm actually struggling to think of a single sport where this isn't the case.

I question your thinking ability.

Happens quite a lot I imagine, for a lot of sports 17-19 years old is about the age they start breaking into the pro team and by the time they're 22 (college age) they can be nearing the start of their peak years.

It happens less frequent in distance than any other sport. Your strawman argument is the opposite of what is true.

It may be better to ask in what non-team sport is it generally impossible for a high school-aged phenom to be world class.

A college kid won a PGA Tour event a month ago

All the time in swimming and most top high schoolers are very technically sound including turns. They are often 10 years in the sport by then.

Your first post was correct. It never happens in distance running but happens frequently in other sports.

women's tennis.

It used to happen all the time and women's gymnastics until the Olympics raised the minimum age for competition for gymnastics. Nadia Comaneci was 14 when she won gold. Mary Lou Retton was only 16 when she won Olympic gold.

Women's golf has had some very young winners. Brooke Henderson won at 18. Lexi Thompson won at 16. Lydia Ko won at 15 and had 5 more wins by age 18. Atthaya Thitikul is the youngest LPGA winner at 14.

In snowboarding, Chloe Kim was 17 when she won Olympic gold. Gaon Choi is 14 and just won her first pro half pipe competition.

The age is now 16. So your point is pointless.

I was thinking along these same lines. I suppose that technically if a high school kid signs with a professional team s/he immediately becomes a pro. Women's tennis is absolutely a sport where high school aged players compete with older professionals but again, when they do that they are professionals themselves and no longer high school kids.