The trouble is that in order to git, somebody has to buy. Selling under such oppressive taxation levels means current owners will have to take an insanely big haircut to be able to leave.
This is not necessary the case for many of these city houses. You bought in 1972 for $45K, and its now worth $2.6 million. If the raise the tax, it might have to be sold for only $1.9 million, but you can still get out. The buyer will take the tax nto consideration, but the $700K reduction represents a flow of about $20K a year even at low interest rates, allowing the tax to be covered.