When President Biden announced his plan to provide student debt relief for 43 million borrowers nearly two years ago, there was a piece to his program that attracted less attention: a new student loan repayment program that would cut monthly payments in half for millions.

The repayment program, called SAVE, was meant to become a permanent fixture of the federal student loan system, offering a more affordable path to repayment, particularly for lower-income borrowers. But two groups of…