Do you have any data to support this? I am not being argumentative, I just found that from personal experience the opposite was true- that total rent tended to be higher in SF, but the apartments tended to be larger, at least than those in Manhattan. It seemed to me that SF was slightly cheaper per sq ft, with many more houses having access to outdoor space.

The closest I could find in terms of data was this site- https://www.rentcafe.com/blog/rental-market/us-average-apart... which compares SF to all of NYC, not Manhattan. The studios are somewhat bigger, the 1BRs slightly smaller, and the 2BRs are on average slightly larger- but the difference is very small.

I'm going just by the bedroom counts listed on that website. It's possible that those numbers are also deceptive because square footage per bedroom is sufficiently different. I was mainly remarking that the breakdown seems to indicate that NY inventory is biased towards 2BR apartments while SF inventory is biased towards 1BR. This is based merely on the fact that the SF overall average is much closer to the SF 1BR average while the NY overall average is much closer to the NY 2BR average.

Price per square foot would shed more light on this, but I don't know of a reliable (free) source of that data.