So why in the world does rent keep jumping through the ceiling in Boston, NYC and SF. Housing prices have gone up despite this 'bust' in real estate. I didn't s

So why in the world does rent keep jumping through the ceiling in Boston, NYC and SF. Housing prices have gone up despite this 'bust' in real estate. I didn't see a single landlord in those cities drop (or hold) their rent, despite how bad the 'drop' (again, which I didn't really see) was.