Regular apartment rentals often lock renters for multi-month contracts (due to difficulty, length, and expense of the eviction process, in which landlords lose money during the lengthy eviction process, when a renter rents for a single month and does not leave after not paying); air BNB, although it's more expensive per night, doesn't have such long time commitments for renters.
You gloss over "other costs". Many anti-AirBnB people's concerns are precisely about those other costs.
It's evident in this discussion who are the people pushing the externalities onto others, and who are the people having to deal with them.
Precisely, there should be no profit incentive. Society doesn't need lazy landlords speculating on gentrification. I don't give a fuck if you're disincentivised to own 8 homes which you can rent out while you holiday in the carribean. Productive societies needs affordable housing for all classes of people. Property is not an asset for speculation or a VC-backed venture return model. Feel free to invest your spare cash in innovation and businesses seeking growth.