The biggest problem with the "let the kids go out there and let athleticism take over" line of coaching without "gimmicks" or video is that we'll end up with the genetically elite, big-at-a-young-age crowd, and athletes who move well out of pure luck in pro sports. That's it.

Some roll out of bed and were born that way, or they luckily successfully imitated the right mechanical pattern (didn't get bad coaching / chose poor mechanics accidentally).

Some kids have to do a hell of lot more to become prospects and get the most out of their bodies.

For years the strategy around player development was just to find the best at a young age and shuffle them along, and treat outliers as luck. Today we realize there is a lot more talent to be developed from a lesser starting point, and that the age/talent curve may differ.

Modern sabermetric analysis is starting to grab this. The age/talent curve is shifted to the right for late-bloomers and injury-laden pitchers. Examples abound like @PeterBayer47 touching 100 MPH for the 1st time at an "older" pro ball age.

It's important to note that projections of players are more accurately like a projection of an average athlete with those underlying statistics and inputs. We are not controlling for organizational philosophies, off-field habits, makeup, who trains them, etc.

It isn't shocking to see the teams listed at the top of @paintingcorner's work (which is the first of its kind that I've seen publicly) about which teams get the most out of their players. Even a 1-2% difference compounds over years. https://tht.fangraphs.com/beating-the-odds-when-teams-outperform-their-projections/