This has been an excellent thread to demonstrate just how many different theories and views that exist about arm injuries in baseball and what can explain them. Obviously the times have changed significantly when it comes to youth baseball and the road toward trying to play in college or the pros. Would the old legends like Ryan and Drysdale have held up like they did had they been brought up in this era?
Many of us with sons on that road are trying to give them the best opportunities to make it there, and these days, it seems harder than ever to get there. From the rising number of MLB pitchers throwing in mid 90's to the elite college programs with pitchers doing likewise, it is no wonder why so many parents and kids are focused on pitching velocity as the ticket to the next level. Truly it is sad in those cases where kids overdid it and ruined their arms before they even got the chance to play college baseball. The hardest thrower on my sons' 12U team cannot even throw anymore as a 16 year old after labrum surgery. But I blame his parents for moving him to a 13U/14U travel team and coach focused on winning tourney trophies at any cost.
Maybe someday one of these "experts" will figure out what the answer is, but for now, it is up to us parents to make sure (1) our sons are playing on travel teams with coaches who place the priority on player development and safety over winning, (2) we limit how much of the year our sons are playing baseball to allow for some shutdown time and arm rest, and (3) we accept that not all of our sons may have the arm and capacity to pitch at an elite level and focus instead on getting them into the right school and situation where they can succeed in college.