Every time I have asked the question of why don't small hotels do All-Inclusive, I have been told it's because you need at least 200 rooms to make it work. Law of averages evidently, you need 400 people to get the proportion who are on a diet and don't drink to balance out the ones who are like whales. There must be a reason that all the AI's are so big when everything else in travel is getting smaller (i.e. planes and AirBnB's).
The discussion on AI's has been in the context of if any AI regardless of size could list on Airbnb. They could if they thought it practical. The biggest problem I see is the price Airbnb charges both the Host and the Renter, which would make the booking less competitive. If a "small" AI wanted to list, they could be very specific about their meal and drink plans so that clients would not book by mistake. True they would have a hard time making a profit if everyone that ever booked just ate and drank 24/7.