not just D1, my sons D3 had 10 in freshman class last September, they have 7 now. One couldn't play, 2 couldn't study. IMO next September of 7 left now there will 4 maybe 5, the good news I think 2 of them will be freshman starters, one of the others is going to be a very good player but he is behind a 3 year starter, next season a sophomore I expect he will be very good.
the failure rate is huge but you can see pretty quickly who is overmatched.