This is why his vapid feelgood campaign that was light on actual policy details was so annoying. No one remembers him actually committing to any damned thing.

In this particular case, Biden did indeed campaign on reducing student debt, if not eliminating it entirely:

“he campaigned on two distinct planks. One: “immediate” cancellation of $10,000 for every borrower as a form of Covid relief. Two: the cancellation of all undergraduate student loans for debt-holders who attended public universities and HBCUs and who earn up to $125,000 a year.”

from www.theguardian.com/commentisfree/2021/feb/25/joe-biden-student-debt-american-students