I haven't found any really detailed numbers for the project. Does anyone know more about how heavily subsidized the housing is, meaning how much the public bill

I haven't found any really detailed numbers for the project. Does anyone know more about how heavily subsidized the housing is, meaning how much the public bill will be each year? The idea that such projects are so popular and aren't necessarily meant to help only those most in need is confusing in what is usually considered somewhat of a free market. Why aren't these types of projects being built privately if they are so successful? And how do you justify subsidizing housing for those making at or even above the average household income level?