You are correct that zoning density restrictions and overuse of historic landmark status create political scarcity of housing that benefits landlords such as Donald Trump to the detriment of renters. The landlords and allied special interests back laws that create "economic rents" -- additional profits not through wealth creation and efficient markets but through the market failure of creating artificial scarcity.

If AirBnb wants to make housing more affordable in NYC, they should lobby to remove these zoning laws that benefit wealthy landlords such as Donald Trump.