If the problem is developers making a bunch of apartments and releasing them slowly, wouldn't such a tax just mean they'd switch to a strategy of making them slowly to get the same effect?
Literally nobody has ever done this. Large apartment builders have banks breathing down their necks. They try to lease up as fast as they can, which generally takes about a year to get to 90% because there's a lot of friction in getting people to move.
The governor of my state ripped toilets out of one of his mansions to make it "unlivable" for tax reasons. No doubt the developers could stall finishing units if they had to.
