This thread is awesome.
If your son wanted to be an actor, would you just tell him to hang it up if he came to realize he was never going to be the next George Clooney or Tom Cruise? or...might you encourage him to branch out onto the stage or theater so that he might broaden his horizons that way. Perhaps he could become a director, agent, producer, writer, character actor, etc. etc, etc, while still pursuing his love of acting.
Baseball is like that as well. While everyone would like to be a big star in the big leagues, sometimes that is not always possible. However, some love the game so much that they will find a way to make a living at baseball. There are hundreds of possibilities.