Local zoning, land regulation and permitting laws create the problem. Toss in urban taxation and spending priorities and voila you have a massive misallocation of capital which prefers fallow to productive property.
Where you find persistent poverty you find socialism.
The evils of which you speak (and we agree, they are evils) were brought in to being by a land holding cartel in order to create scarcity and increase its wealth. Socialism was a failed attempt to deal with this scarcity by controlling labor, capital, and land. Georgism , OTH, frees labor and capital, and allocates to society the wealth that it created, the value of its land.