I agree with you that the definition of affordability has become a lot more elastic as funds have been scarce to create supply programs for co-op and non-profit housing. The only way to generate deep and continuing affordability is to reduce the capital cost of developing new housing in the first place and reduce the cost of financing that debt over the long haul. That's the source of funds that have become more difficult to access at the federal level under some of the recent programs.
Now, it is true that housing is never more expensive than on the first day it's occupied. As long as it's being run on a not-for-profit basis by a co-op or a non-profit housing provider, it will become more affordable relative to the market over time, but people who can't afford a place to live now don't have 10 years to wait while you pay down the balance of the equity on the loan. They need affordability now. That requires a deep capital and operating subsidy for the development of those homes.
I agree with you that we shouldn't expand the definition of affordability to fit the resources that are available to develop homes. We need to establish that benchmark at 25% to 30% of income and then deliver the subsidies that are required to get homes into the marketplace so they can be occupied by the people who need them the most.