Of course rent control effects supply, because it alters behavior. You can debate how much it affects supply and the availability of affordable housing but I do

Of course rent control effects supply, because it alters behavior. You can debate how much it affects supply and the availability of affordable housing but I don't see how you can claim it cannot have any affect. One of my friends lives in a rent controlled apartment for example. It's a 3 bedroom apartment that he lives in by himself because it's cheap enough. He was transferred to work overseas for 6 months and kept the apartment because if he gave it up when wouldn't be able to get anywhere close to the same price when he returns. That change of behavior due to rent control now just took a 3 bedroom apartment off the market indefinitely.