The big impediment is the lack of availability of buildable (as allowed by zoning laws) land.
Much of the unused or underutilized land in my area is owned by Federal, State, and Local Governments or set aside as "conservation" land.
As part of the gentrification of my area, developers buy 1,000 sq ft ranch houses for the land they sit on, tear the building down, and erect a 2,000+ sq ft colonial or McMansion. So, exisiting affordable housing is being destroyed to make way for new unaffordable housing because of Government land restrictions.
A viable way to solve this is to provide towns with bounties for each 3 bedroom, 1.75 bath unit of housing they add. Cut state funding to towns, and make the towns supplement the reduced state funding with housing bounties. Also tie state school funding to housing bounties.
Maybe even tie state funding to towns based upon number or % of 3 bedroom, 1.75 bath dwellings exist in the town.
Those town that contribute to the solution get the reward; those towns that don't, get the shaft.
Prison cells and Over 55 developments no longer counted as "affordable housing" in the housing census.