Something I want to add that I feel may contribute to some of what I believe the players are thinking
Before social media and the information era the only thing players really had available to them was the coaches they directly worked with. HS Coach, maybe a private instructor. Then college staff, and summer league coaches. You could walk away from your college career with quite literally 2 or 3 opinions on improving your game.
Now any kid can fly to Driveline and live there instead for an entire summer. Any kid can hop on YouTube and watch hours of Tom House material. Even twitter, PitchingNinja, pros, etc. In between reading thoughts from your buddies and the news you can have another perspective on pitching, hitting, fielding that was never available to you before.
I'm not saying the coaches in summer leagues are not good, not at all. But with all the information and material out there I feel like kids are more likely to get a lot of options to look at and stick with what works best for them. The opinion of their summer league PC or HC is less valuable now than it was years ago for most collegiate level players. Especially when it is obviously a situation where a coach is looking to get some experience and make his way thru the ranks as opposed to having a firm track record.