That's why they're called $tealers. You have to remember that you (we) are not their target clientelle. They cater to people with lots of money who don't care about the cost. So no, they don't steal from "their own"
I just bought an '88 Targa and have two points to make from that:
1. The car came with full records and both previous owners had all work done at dealers. The bills are mindboggling. There is no way I'd buy that car if I wasn't into DIY.
2. The airbox was broken and there was some back and forth about whether they would replace it since it's expensive (I happened to find the car at a Porsche dealer). Anyway, the point is that the list price of the airbox is $270, but dealer cost is around $150. That's an insane markup! Esp, since dealers don't bother carrying inventory.
Anyway, end rant. Happy Friday!
Stef