Marianne,  I know that premies were involved in starting Rainbow in SF, but my understanding is that it wasn't exclusively premies who started it, and it was never a cult business like the stores in Chicago and Denver were.

By the time I got to San Francisco in 1980, Bill Crolius was still working at the store, but the store was completely worker-owned and most of the workers were not premies.  Rainbow in SF has always remained worker owned and really is a true co-op (worker owned and not customer/member owned).  Rainbow in Chicago claimed to be a co-op, but it never really was for the reasons Babaluji mentioned.   I think Denver was the same way.