At the extreme end, one thing that they'll do is become a slumlord - have noncompliant housing that isn't registered. Yes, it's illegal, and the penalties are

At the extreme end, one thing that they'll do is become a slumlord - have noncompliant housing that isn't registered. Yes, it's illegal, and the penalties are severe if the person is caught. But it's an option. And if the current owner is sitting there thinking, "Shit, I can't rent this building out and make it worth my while," (property tax, cost of keeping it up to code, etc) he'll sell it to a slumlord who can make a profit out of it.