For a quick order of magnitude comparison, taking SF as an example - as near I can find, there are somewhere between 5k and 10k airbnb listings in the whole bay

For a quick order of magnitude comparison, taking SF as an example - as near I can find, there are somewhere between 5k and 10k airbnb listings in the whole bay area. But to be very conservative let's assume 10k and assume they're all in SF itself. Well between 2010 and 2015 SF added 150k more jobs than housing units. Meaning to get back to 2010 levels of affodability SF would have to add on the order of 150k more housing units (and that has probably grown even worse in the past 3 years since 2015). Airbnb is unfortunately just a drop in the bucket.