The reasonably priced Lite models from Silix and others have the 28K movement, to further confuse the issue. The bottom line is, as always, the manufacturers are extracing the maximum amount possible for a desireable item with a limited number of suppliers. The movement type (21K or 28K) and bezel material (ceramic, PVD, or plated) DO affect the manufacturing costs, but only slightly. The retail price is comfortably high, borne by a massively inflated price when the replica was new--the manufacturer(s) are trying to keep the bubble inflated as long as possible.
Some comparisons:
Silix SS HBB (Lite) with PVD bezel, 28,000bph high beat: $245
For whatever reason the Silix Ice Bang lite costs more: $315
Watchmark PVD Luna Rossa with SS bezel and 21,600bph low beat: $295
So you get pretty much the same price for the watch with the inferior movement.
I wish someone would do a side-by-side comparison of the 21K and 28K watches. I remember reading about them when the new rotor stickers were first spotted, but they were dismissed as low quality although I don't really remember where I saw that. Since they are made by different factories it would be good to know all their differences.