So if someone doesn't have enough accumulated capital or credit to buy a property to live in, tough luck. You can't legally rent from someone. I guess rely on charity or sleep on the streets? Seems unreasonable.
I think that ceteris paribus the lower housing rents are the better. How to help bring that about is an interesting policy question. I suspect that socialisation is the best option, but increasing the stock and rent controls could work.
If we return to the specific case of AirBnb and my original suggestion, the aim would be twofold:
1. Limit AirBnb rentals to reorientate the housing stock away from rich international tourists to locals.
2. Tax AirBnb rentals to subsidise local housing.
I would point out that Barcelona has already done (1).
'Renting' in its essence does not involve doing anything: it does not mine resources, manufacture use objects, or provide a service. Rich people buy up scarce assets and then charge a fee for their use. The return has no correlate in any socially useful activity - it is 'profiteering'. AirBnb means it is often more profitable to buy properties and rent them to rich international tourists rather than to locals. This creates the further, perverse effect of pricing out residents from their own cities. Given than I am a democrat and think societies should be run by and for the people, I think this is obviously remiss.