What are some good West Coast USA flower and vegetable seed sources?

Somehow it seems that all of the large, well-known firms that sell flower and vegetable seeds nationwide are in the East. Firms such as Johnny’s Selected Seeds, Park Seed, Stokes Seeds, Gurney’s, Thompson & Morgan, etc., are all located in the eastern part of the US. Why is that?

The only western one that I know of is Burpee’s. Since what grows well in the east may not grow as well in the west, I’m interested finding more seed firms that you have personally used that are reliable and that have good products.

Just so you don’t misunderstand, I’m not unhappy with the above-mentioned firms. I’ve used all of the them in the past, and they’re great, with excellent customer service. (I used to live in other parts of the country.)