Highlandermom,
I tend to disagree.
My son has cared about every "W" or "L" he has had in his minor league career. He really cares when he is removed from a game(due to pitch count limits) in a position for a "W" and then has to watch from the bench while others turn his "W" into a "L". He also cares every time he takes a "L" due to poor defense or lack of run support. And... he cares extreemly much about the couple of times that he has not been able to be on top of his game and feels that his performance has let his team down.
Those in charge who are watching the minor league performances also care about which players display a winning attitude- even if the team is not always doing so hot. Ultimately, the really successful MLB players are the "winners" who make it through the tough years while others may not have as great of a winning attitude.
At least this has been my experience through my son's 2 minor league seasons. Attend a minor league post-season play-off game and see if you see anyone caring.