I have run a successful small business, and let me say right now, you charge what the market will bear. If you are trying to get market share, you undercut your competition. Don't ever believe that business school crap about companies' margin being a few (1-5) percentage points. You charge what people will pay, and typically your big clients (think large corporations and the government) get a good deal, as they are paying your fixed expenses to keep you afloat, and the smaller clients (small businesses, individuals) get the worse deals, as they are where you are making more profits.
One of the ways to convince people to buy things at a large margin is the "snob appeal" factor. As in the Mercedes and Bentleys mentioned earlier. In those cases you pay more than you objectively get.
As to the manufacturing tolerances, I thought the whole idea of CAD/CAM and CNC was to improve quality and lower manufacturing costs. As for R&D, how much of that can there be for 30 mm scope mounts, vs 1 inch, really? And you are spreading those fixed R&D costs over hundreds (thousands?) of units. Also, aren't these companies also producing other products so most of the equipment is a sunk cost (unless it was bought just to produce 30 mm scope mounts)?
But don't rain on someone's parade, if they want to start a business to produce a better product at a lower cost, we should all encourage them. It's the American dream, and if they succeed, we all benefit.