[bombcar]

Another problem is AirBnB almost by definition are less dense than hotels.

If there were no AirBnB, the economics for a new high-rise hotel would be much better.

But it all comes down to increasing desirable supply (which may be density dwellings at the end of an express train) or building entire new cities (or rejuvenating others).

At some point, if supply outstrips demand, prices will start to stabilize - maybe fall.