> The wealthiest schools would absolutely love this.
No, because:
(1) Their "best and brightest" branding requires at least the perception that top geniuses from families of modest means still get in.
(2) A perceived "You must be $THIS rich to enter" sign at the door - for anything, not just education - attracts a lot of negative reactions these days.
(3) They can feel a slippy slope under their feet. There's a lot of Federal money flowing into their coffers (both literally, and de facto), and no reason for Congress to stop at cutting off just their Federal student loan money.