There were definitely independent telephone companies in California. The big cities were Bell territories, and their outlying areas probably were, too. The independents would have been found in rural areas (or areas which had once been rural). But keep in mind that independent rural telcos weren't the only companies that used equipment from independent manufacturers. Independent office telephone systems used non-Bell equipment in vast quantities within Bell territories. But residences were a different animal altogether. Whereas you could easily find several telephones of various manufacture on a businessman's desk, you wouldn't find that situation in his home. The telephones there would have been all Bell, or all Kellogg, or all AE, etc., depending on where he lived. Bell was a monopoly, but that didn't mean they controlled everything.