It's an easy statistic to calulate, look at the signing class that made it to campus in the fall and see who is there in the spring. And again who is there the next year. Most of the elite programs have the info available.
schools don't brag on how many players fail to make the cut because it would jeopardize the pipeline. Reality might hurt the dream.
it doesn't matter to most top players because they haven't not been the Man and think they will still be in college. Failure is too foreign to even consider. Typically 50% are wrong. Choose wisely.