Unfortunately, it doesn't seem to be working out that way - housing that was used for permanent residence is now getting converted into airbnb rentals. People are now acquiring properties in order to have a "spare room" - ands those "spare rooms" would absolutely be occupied by a long term resident if they were not being used as short term hotel-like rentals. For instance, people are now using the anticipated income from a spare kid's bedroom to outbid a person who would have otherwise used that bedroom for, well, a kid. Kids cost a bundle, and they don't pay anything like a well heeled tourists for the right to occupy their bedrooms. In a place like SF, where everything goes to a bidding war, a family with the extra costs of kids has very little hope going up against an investor who plans to convert the house into a hotel.
BTW, I absolutely agree that some of this really is efficiency (spare rooms, people on vacation). But at this point, I think it's pretty clear that airbnb is driving displacement and conversion on a large scale.
It is immensely reasonable (yes, in my opinion) for cities to pass laws that ensure a proper mix of housing, including housing for families with children. These laws are not obsolete just because someone wrote a Rails app where you can type in an address and click a "Create Hotel" button.
I overwhelmingly agree that SF needs to build more, but I don't think this basic reality will change. SF's population of children has plummeted in my lifetime, from about 22% to below 14% now. Airbnb is hardly the only factor, but I believe it is making the problem worse.
