Cheaper mortgage rates equal more expensive housing - supply didn't magically increase.

Cheaper mortgage rates means institutional capital that was otherwise sitting on the sidelines in T-bills will be deployed directly into that remaining supply.

Just start building already, 6.8 % for the 30-year fixed is well within historical precedent. High housing prices are a result of asset inflation for a product priced at the margin. Only way around that is to increase supply.

(Also consider this: there is nothing more unproductive than real estate - the stupid capital must be forced out of the mattress and into productive ventures.)