Right now, single family homes are exempt from rent control. An owner can raise the rent as they see fit (within reason). If SFHs come under rent control I think you'll see a lot of people just not renting their homes or condos out at all.
This happened in Toronto last year. Similar to SF, units built after 1991 were exempt from rent increase limits. Now it's all units.
So if you owned a condo in Toronto and it was worth $600K, it's probably worth a lot less if you're currently renting it out because that tenant has just locked in their rent for the foreseeable future.