"This new wave of Uber competitive sports is only about 20 years old"
So this is a 20-year trend, but 22-year old kids aren't old enough to fit into the last 20-years of data? How many generations need to pass through before we have acceptable data for you?
Kids didn’t start specializing until the mid-2000s for the most part. So it stands to reason that most all professionals right now played multiple sports.
A lot of it came about because of Malcolm Gladwell’s book about the 10,000 hour rule, which was published in 2008.
Most all the Latino players played nothing but baseball. So there are data points everywhere. Of course they aren’t playing travel ball tournaments, they are practicing athletic movements.
The key to all of it is making sure you develop athleticism, and get as much experience as possible in different situations. And proper rest/recovery. “Play multiple sports” is good advice for most kids, but it’s important to look deeper.