Supply and demand. Plain and simple.
Others will chime in about unfired/new vs. refurbished, and Chinese being more accurate, blah, blah, blah...
The Russians are better made, have nicer wood, and are nicer finished, and if you can find a mint non-refurbished example, even better!
Now, the current mega-shipments (yes, NO shortage folks!) from Westrifle are not like they were 2 years ago, but some are still nice.
As an aside, I always get a kick about meaningless price comparisons when it comes to the SKS, when I spend more on ammo and small accessories for other rifles. Who the hell cares about a +/- $100 (at most) difference between a pristine Russian, a Chinese, or a typical refurb Russian? If you intend to use it as a bullet hose, buy an average Russian refurb and treat it like the b*tch that it is!