Great post, Crash. I was also fortunate enough to have had lessons from many of the coaches you have mentioned. These included John Jowdy, Mark Baker, Bill Hall, Fred Borden, Don Johnson, and most recently, Jeri Edwards and Mike Shady.
Many bowlers don't realize the point you made. They often think that the next new
ball release is the answer to their game. It's only when they begin bowling in a competitive environment, on competitive conditions, that they will then come to the realization that it's more than just the ball that is preventing them from stepping their game up to the next level. This is where a good coach can make a real difference.
A coach cannot "teach" talent, which is a fundamental prerequisite for those aspiring to reach the very top of this game, but they will elevate a bowler's game far beyond
what he/she can to do on their own.
In the 50+ years that I have been bowling, the money and time I spent with these
excellent coaches by FAR, was the best investment I ever made.