But see, it is the philosophy to take a bunch of kids and turn them into men precisely because it will make them a better baseball team and win more games. And a college coaches job is not only to win games but to run a clean program, and develope young men to transition to the next phase of their lives. You are thinking of professional sports.
As a parent I would hope my son's coaches at every level help develope him into a man. A mature adult who is disciplined, selfless, responsible, and accountable. Because that will make him better at whatever he does, including baseball. It's my job to do that too, but I would hope every authority figure in his life would contribute to that process. I would rather my son play for that guy than the guy who doesn't care about him, only winning. Robe's approach is better for recruiting too if parents and their kids think the same as me. It all goes hand in hand with running a successful program.
With your preferred approach you have a bunch of immature individuals who don't end up caring much about winning ultimately. They are selfish and don't play as a team, which leads to losing. For a reference, go look at most minor league teams.