Talked to a coach of one of these big schools when my son was looking last year. They have 140+ kids in the program.
Already knowing the answer, I asked him how many freshman were currently in the program.
He responded that there were 25 kids on the freshman team.
Not what I was asking. He conveniently forgot to mention the additional 15 freshmen on JV, and 4-5 on varsity.
But that team did have 12 seniors.
So they likely started with 40-45 freshman hopefuls.
The reality is that 3 out of every 4 freshmen at these big schools, won't be rostered by senior year.

Your kids only have 4 years of high school. Tell them to go where they can play. It's more fun to play.

Trust me.