No, it is better to get guys to produce, regardless of whether they need a carrot or the whip, than to have them quit. They failed to do so. It is a tough task, but figuring out how to get the best from a young guy is the primary challenge of being a coach.
The antiquated single-minded approach works great for movies and romanticizing about teams of long ago, as well as teams with an abundance of natural talent.
I'll disagree again. If a player is so mentally weak that he quits on his team because he was challenged to elevate his play I don't want him on our team.