It's not reasonable to consider all rent-controlled housing off the market, however. Most don't have tenants pay a rent substantially diverging from market rent. People constantly move, even if they are in a rent controlled apartment.

To wit, I'm "Rent Controlled" in SF, but since I moved apartments last year, my rent is controlled to something north of $3k/month. I've had several other friends move recently from and to other Rent Controlled units. Saying a large swath of the city is rent controlled isn't very informative without actual rent data.