If I understood his argument, I think he was saying that only non rent controlled apartments are factored into things like average rental price. So, in this case, the rent controlled properties are basically just not part of the market right now. So his argument was that removing the rent control would more than double the apartments on the market. The price for the rent controlled properties would increase but since they previously weren't being counted, the average price would ultimately drop with the larger supply now available to be bid on in the open market.