I don't like comparing cities' density numbers as given by Wikipedia because many cities, Berlin included, include large areas that have really low density. Berlin for example has more than 4000 hectares of forest inside its city limits where nobody lives. If you go by these numbers, SF is denser than Tokyo.

Yeah, was trying to get at that with `has more surface area to spread out`. Suburban sprawl doesn't work as well in SF.

That seems like double-counting, then. The density numbers are based on the total area divided by the total residents. If the residents are squeezed into half the area, it should not be said that there is lower density and more space to spread out. The lower density is already because of the space.

I don't think so, the point there is that SF physically has no room for suburban sprawl because it's a single stranded peninsula. Berlin is both currently less dense, and also has further room to expand geographically. One might disagree but it makes sense that way to me