I think part of the reason that so many bullpens are full of tall athletic white lanky kids throwing 95+ in recent years is that they have started choosing baseball instead of trying to compete with tall athletic black lanky guys at younger and younger ages in basketball.
You are right about the physical requirements in football and basketball. The great equalizer in baseball is hitting a round ball fair with a round bat, especially when it’s 90+ and your timing is messed up with slower breaking balls and change ups. If you can do that, some of the other more physical skills that might be lacking don’t matter as much.
Probably the greatest hitter of all time Ted Williams said hitting a baseball was the hardest thing there is to do in sports. He would be asked how he was so good at it and he would say he practiced all the time and still missed more than 60% of the pitches.