Well, for the people who have a tent controlled apartment it's certainly not terrible for controlling cost. Be more specific.
>because people in rent control places will not leave.
What kind of details are you looking for here? That they don't leave because it's likely the lowest possible they would be able to find, and that the tenants would be increasing their cost otherwise.
the competition for a place is high in the bay area, so even if they find and apply for an apartment doesn't mean they'll get it. my personal situation is worse due to me finding rooms instead of entire apartments. lived in 4-5 different places in last 4 years. I would get a response rate of ~5% from craiglist when looking in SF, percentage better in the peninsula. Usually competing against 10+ people viable applicants each time.