This is the same thing happening with cars. There isn't enough new car inventory so used cars are going higher and higher. Dealers are buying used cars for MORE than people paid new. As already built houses for sale continues to rise, new construction and rents will rise too. The market is adjusting to make all choices equally bad.
I'm starting to see dealers sell at, and in some cases above, the cars MSRP. The value proposition of buying new is shaky enough during good years, I cannot imagine buying a new car above MSRP.