> Why accept candidates that will ultimately go elsewhere?
Idea: When you apply for a college, you have to prepay for the first semester. If you get admitted, you have already paid for the first semester. If you get rejected, you get this advance payment back. On the other hand, if you get admitted, but decide to go somewhere else, you loose money.
This should give the university a strong incentive not to reject strong candidates that will go somewhere else - quite the opposite: if you admit such a candidate, but the candidate goes somewhere else, the university earns even more (the semester fee without having to provide any service for this money).
Interesting idea, but look at it from the applicant’s perspective: you’d have to front like $50,000 to apply to just 5 schools (if you call $10k the average price for a semester). Even if you solved the financial aid question here, admissions is a numbers game for students, usually, so getting accepted to more than one school would dig the student loan debt hole that much deeper across the board.