The principle paid down on those repayment mortgage came from homeowner income and was diverted away from other savings and investments.

Punishing millions of people who just sought housing security because, for reasons beyond their control, the Fed decided to cut rates after the GFC and keep them low for 15 years is just not tenable.

Fortunately, in the UK at least, it looks like (nominal) house prices will remain stagnant until real earnings catch up with rates. A better all round solution.