They sure aren't. I'll use the example of west side Cincinnati vs east side. The Chrysler dealer on the east side thinks your car is over the hill at 90K miles while the west siders think it's just broken in.
When I had a "condensation" problem in my rear tailight the east side guys said we'll replace the lens for $350. The west side dealer said, sure we can do that or we can drain the water out of it by drilling holes in the back of it and then seal the holes in epoxy, $65. I never could tell where they drained it and I never had another problem with it.
Example 2: I had a "cranky" power antenna. I asked the east side dealer if I could buy just the antenna since the motor was still working fine. Answer, no, they only sell the whole thing as a set, $300. I call the west side dealer answer: Sure, they sell just the metal antenna and plastic lead on it for $80.