Many hotels do charge unjustified amounts of money, so I am personally happy there is an option to pay reasonable money for good service. Also, it's not like hotels don't have their share of problems. Many hotels in many countries offer you pure garbage when you arrive, mix rooms, bad food, etc. And in many hotels, you can't sleep because of loud tourists or your hotel neighbors. With Airbnb when you find a listing with 30+ 5star reviews, at least you are sure it matches pictures and description.
So obviously, Airbnb has its flaws, just like any other service. But hotels are definitely not the solution to them, at least from a tourist's point of view, though I absolutely see how they are for some local residents.