We should grasp that the home loan market (big chunk of US economy) was engineered to subsidize suburbia. It was made to power the transformation of the US economy from a war footing. It succeeded wildly for a few decades, but painted the economy into a dysfunctional corner. It will never fund enormous unmet needs.
A new system of finance must be engineered. Cities in the US are in a position to finance; globally something is needed.