20k-30k is only a problem for a recent purchaser in Jackson Heights.
The real problem for the real estate is the non-liquidity.
Right now, very few people want to enter the market.
Just using my own apartment as an example, the price has been doubled after the past seven years. I'm even willing have to 10% drop if it can be sold right away so that I can purchase a bigger apartment with the proceeded sale.
However, if I put the apartment for sale, it is going to be involved with a lot of work. Say with 10% drop and some buyer jumped in. Due to the long process, if the buyer wants to back down his purchase due to the price further drop, (there is some legal protection to prevent this to happen, but I'm not going to be dragged into a legal battle who only profits the lawyers), I'm back to square one.