I don't think this is as much of a problem as you are making it out to be. If the east village, which is currently mostly zoned R8B[1] were tomorrow to be substantially upzoned (to say R10) you'd see lots of new construction within a year. There'd be so much money to be made that deals would happen.

[1] http://www1.nyc.gov/assets/planning/download/pdf/zoning/zoni...