Where tourism is, economic activity thrives. Local population grows. => there's a shortage of housing, especially in city center, where people want to live, and want to go. => there's a competition to own the land/housing between: people who want to live there, and people who want to rent it to tourists (lower investment than if you lived there and high+frequent demand). => there's also a shortage of hotels AND a temporary shortage of convenience (precisely where AirBnB thrives with VC money, in order to break and change the market - that's very intentional).