[pwnguin]

The California model of rent control limits the amount you can raise rent on a tenant, and the reasons you can evict someone. Surprisingly, you can often transfer a lease to a family member, leading to situations where someone is living in a rented house originally rented to their grandparent.

It also leads to situations where an empty nester has spare bedrooms but cannot afford to move into a smaller rental unit, effectively taking bedrooms off the market and making prices higher for everyone. Presumably AirBNB relieves some of this pressure, though I seem to recall some landlords running sting operations in order to evict long term tenants and reset the market rate.

Over the past 30 years of SF rent control, this dynamic has created a group of people for whom in-fill redevelopment would be disastrous: they'd lose their rent control, and definitely can't live here anymore. Much of SF is pretty low density, and housing supply would come from building up. Doesn't need to be a 60 tower millenium tower deal. But you'll need to tear up some buildings to make it happen, and the cheapest properties are the ones under rent control. So anyone campaigning on a 'build baby build' platform is more or less running a platform of evicting the poor and/or elderly.

At it's core, rent control is treating the symptom of high prices rather than the disease of tight supply.