"Most" is a broad term. I know in the Dallas are, a few stores are "owned" as one-of-two, and at least a few as one-of-three. In the cases I know about, someone had to "own" a successful stores for several years before they were allowed to try for a second.

I think multiple locations is a thing, if you can prove you can operate one at very good ratings. Didnt realize exclusivity point, though.