I know two people who rehabbed a $1 house ,each, in DC in the 1970s.

They said the project was only possible as the banks were provided guarantees (by the Fed Gov) to make first and 2nd mortgages, without the fear of loosing money if the homeowner defaulted. Also the houses were first for owner occupied, then they opened it to some small time developers. Restrictions were applied to prevent flippers from giving the places a coat of paint, and reselling in a coupe weeks.

My understanding of the Baltimore project, is that it was similar to the DC plan. Lending institutions do not want to loan large sums of money for a shack. But with FED & State backing they did make loans.

Both people in DC, I knew, felt that the program was a success until they had settled into their newly rehabbed houses. It was then that the city zapped them with high property tax. Not so bad for the person who did a row house in a strip of houses which were in different conditions, but the guy who renovated a single family home on 16th street NW, not too many block from the Maryland line. The new tax on that house made it too expensive to live in, for the owner and he had to sell. Not at a loss, but not at a fat profit either.