In the case of Turners I'd say your paying not only for their overhead but for all the bullshit that they have to go through to keep CalDOJ from crawling up their asses on a daily basis.
Other shops have thrown in the towel and given up. They just keep selling everything that they can do so legally in this screwed up state and they do that by being totally anal (in a good way) about the rules and paperwork.
In "Free America" you have a choice and there are many dealers to choose from. In the PRK it's supply and demand and the demand is still high and the supply is not as good. Prices will always be higher under those conditions.
Out of the 17 firearms that I own, all but 2 have been purchased from Turners. I might be able to shop around and save a few bucks, but it's not worth my sanity. We've been VERY lucky in that almost everyone that we've dealt with (except the noobs) have known their shit. Even the noobs, along with the old-timers, have provided outstanding customer service.