So they gots to go.  Such is the case in East Harlem.  From Shagya blog:

From London’s Grosvenor Square you can’t see East Harlem, but you can buy it. For £250 million, 47 buildings, and 1,137 homes at a time. That, at least, was supposed to be the deal for UK-based investment bank Dawnay Day Group when it reached across the ocean last March and snatched up entire blocks of this historic neighborhood of low-income immigrants ­ one of the last such communities left in Dawnay Day Group’s plan follows the typical logic of displacement for “development,” a logic well known both to real estate profiteers and to the poor people they displace.

Here is the full blog post.  It’s nice to see people fighting back.  Here’s a radical thought, if a family is making use of a scarce resource such as an apartment and the landlord is not and cannot use the apartment for its primary purpose then the family possesses the apartment.  It sickens me to see things under-utilized because people with capital choose to sit on them.  Let the property rights fracas ensue.