It’s not the regulations, generally. Hotels are simply more cost effective for corporate management and ROI. If you want to make 20-25% a year you maximize units and minimize land expense and labor to manage. That it costs $10-30M is not a barrier to entry for a large corporation. AirBnB is less profitable but has substantially lower barriers to entry, especially if you lie about owner occupied status (which nearly all do when starting it).

The regulatory angle only really gets put in play because the land is cheaper due to improper zoning (residential is less expensive than commercial) and if the owners are dodging taxes.