The New York Post's Adam Brodsky has a column explaining New York's affordable housing problem:
New York's affordable-housing programs hurt everyone who isn't lucky enough to get a subsidized apartment, because they take those units off the market. Subsidized tenants have powerful incentives not to relocate — even when, say, they become empty-nesters with rooms to spare.
All that hoarded housing limits the supply available to anyone who's looking, whether kids who just moved to town or growing families. That drives up rents and purchase prices — and makes it nearly impossible to find an affordable place to live.
New York now regulates the rents, directly or indirectly, of some 1.3 million units, more than 60 percent of all rentals and 40 percent of homes. We've built or converted hundreds of thousands of apartments priced at below-market rates. It's wreaked havoc with housing — and yet, we're no closer to satisfying demand.