I found that making my own starter(s) was very rewarding.
It takes about 10-12 days to get one booming that is designed to thrive in my area.
A wet foreign starter might work for a run or two, but will transition into a local starter.
With a dry foreign starter, it will/might give you a small head start for the first run before it starts to transition into a local starter.
My point is that a true San Francisco area starter will not or can not live in an area that is not identical to San Francisco areas and I don’t think any area is identical to San Francisco.
This is why areas like El Paso and Denver don’t have similar breads.
I don’t bake my bread near San Francisco and I can’t say that my sourdough breads are the same.
I actually like to think that mine are as good or better than the run of the mill SF area loafs because of my craftsmanship and location.
Yeah that’s a pretty bold statement.
I base that on taste. I travel back and forth quite often compare the breads.
I can give the bread extra hands on care that commercial bakers can’t, I also use no additives and only make small batches.
Last but not least I have pristine water with clam & oyster beds in my often foggy backyard.
It’s a very similar (but cleaner) environment to “you know where”

.
I’d wager that my location is the main ingredient if I’m being honest.