The science for pitching and hitting mechanics continues to refine, but I agree with @adbono in that a lot of people are looking to make their living off youth baseball. There are lots of former college and pro ballplayer in that space because it's a good fit for their experience and a degree in sports management (or something similar).
While in HS during a Tom House camp and based on run-and-guns, Tom told my son he had the potential to reach 100mph or slightly above (he was a junior that touched 88 at the time). He was pretty dead on, how he knew that or if it was SWAG (scientific wild ass guess) based years of knowledge I have no clue.
I'll just add that arm care and strengthening the deceleration muscle groups is critically important. IMO, all this max effort all the time can't be good long term.