micdsguy,
The kids who make the all-star team year after year are the ones who go on in baseball. Even the very, very good kids who are born in July have had a large disadvantage when it comes to making all-star teams and getting on travel teams. It seems like being the stud player is more advantageous than playing with older kids unless a player is good enough to be a stud with the older kids.
When they get to HS they are back on even ground but they don't get much of an advantage because a lot of those August, September, October, November birthday kids have been held back (especially the ones who also play football).
Rumor has it that the AD of our HS and another football coach are going to hold back their 14yo 8th grade sons by enrolling them in a private school for a year so that they can be 15yo freshmen and get more playing time in football.