Depends, the bay area has a lot of fucking grass, especially in the burbs which makes up a lot of the actual greater SF bay. There is people who are doing something like you said but moss or undergrowth lawns are more popular than that. I only have one neighbor in a 5 block radius who has done a gravel/Zen inspired front yard, but there is probably 6 or so non grass yards too. Grass is still overwhelmingly the dominant yard.

In SoCal I saw a lot more variations on what people do, a lot less uniform than many parts of the bay