First, huge hotel chains are an American thing, the rest of the world (Europe in particular) is managed by many smaller players for which you cannot have numbers.
Second, the American chains are a fairly stable and fixed business limited by physical buildings, AirBnb is worldwide and extending to 100 countries as we speak. The current hotels vs airbnb state in America is already determined BUT only valid for America. What will be the market shares per country and cities... this has yet to be determined. Meanwhile AirBnB starting from 0% everywhere else is enough to justify growing income and revenues.
Third, there could be 10 (or 100?) times money stuck in the black market. (People who pay hand-to-hand, rent to a friend of a friend, gumtree, newspapers listings and the likes). AirBnb can tap into this black market and make it emerge, whereas this space is irrelevant for hotels.
You wanna talk business. Please compare numbers from hotels.com and booking.com and airbnb.com