I think you still need to differentiate between the NT and U21 levels in this argument. Maples is irrelevant to the conversation.
The thing about training a U21 player that everyone neglects, is not the salary, but the results of the team. Were Terrance Hammond and Mike Merrill and Jimmie Brown expensive for the teams? Absolutely. Are they even more expensive and probably overpriced now. Hard to argue that!
But lets take a look at how their owners fared in each of those players 20 year old season:
Terrance Hammond: In season 16, Newmarket West Siders were crowned champions of league Canada III.11
Mike Merrill: In season 16, Hamstar Hoopers were crowned champions of league USA IV.47
Jimmie Brown: In season 16, West Lawn Mowers were crowned champions of league USA IV.61
That is not a coincidence I will assure you.
Rambo got vilified for playing PTB in the America's semi against Argentina.
Hey I won that game though!!