Uber, Airbnb, and many of these other 3rd wave tech companies are more legally inventive than technologically innovative. They all make money because they lower costs by circumventing laws. Hotels have to be ADA-compliant and their fire systems are tested.
Virtually every lease I've signed had clauses about subletting, with precedents on those clauses being enforced.
Virtually every condo building have bylaws against short term rentals.
Pretty much all towns have zonings that would cover these things.
While the applicability of some of these is up in there air, at least SOME of these rules apply and would drastically reduce the feasibility of some of these rentals...but Airbnb makes it so easy in comparison with how hard it is to do something against it.
We're starting to see some enforcement but it almost always goes against a small guy. Airbnb isn't getting fined, the small family business is. Uber drivers with criminal records, driving drunk, assaulting passengers, and without commercial insurance don't get Uber in trouble either.