Earlier quoted context omitted.
Not to mention those places tend to be much flatter. In the west Bay Area you have to ride next to 101 unless you don’t mind hills.
Most of the heavily populated places in the bay area are fairly flat, so that's not really a problem. Plus, with ebikes these days, hills just aren't the barrier they used to be. The problem is mostly just infrastructure. Almost no California cities have more than a piddling amount of safe transportation biking support.
Cities with lots of hills in Europe don’t have as many bikers or biking infrastructure. Eg Lausanne unless you want to go for a jaunt by the lake. Cannes was the similar during a short visit I made 20 years ago. Hilly south Europe (Athens, Rome) doesn’t seem to like bikes very much either.