Agree @suzyQ7 , but they usually have some connection at some schools, and then, only to give a nudge to qualified applicants. This influence would evaporate if the CC recommended students who did not succeed there. And to that end, CC is probably recommending students who will flourish there regardless of whether their parents donate. That’s part of how they pave the way for future classes.
Your point highlights that a gift can only have limited impact, though, and often in situations in which it probably isn’t needed.