Just talk and money for allied lobbying groups/people. You go into an underserved community and tell them "we're gonna tear down these 18 blocks of old homes and run-down apartments and replace them with new construction that can fit 4 times more people with better amenities"? Never gonna happen. You're going to displace all the current residents, who will protest. Then you need the local zoning and construction people to agree. Then you have to pay for it. And if you accomplish all that, maybe in a decade you'll have some nice new apartment complexes that will be more costly and all the previous residents will have new lives somewhere else.
Now if they actually wanted to do it, they could. You get it all lined up in advance and you pay the developers/contractors a bonus for every day they save in time completing the project, and you give the displaced residents first right to move into the first units ready for occupancy. But that isn't how it will work and everyone knows it.
All this will do is end up buying some electric buses that say "brought to you by Biden"; and line the pockets of people who work for advocacy and interest groups.
Two words:
Cabrini Green.....................
Anytime you read about new, low cost housing, merely divide the number of persons who will be served by it into the projected total cost of it.
The answer will ALWAYS be more than buying a complete new house for each person!!
KEEP in mind: You can NOT make STEEL without fossil fuels.