I don't want to unfairly knock import parts either. We've all used import parts which surprised us and held up well. Fact is, they sell and make more cars in China than everywhere else. Their factories are, in general, more modern, use the latest and best equipment, and chinese people are (usually) quick to make changes ...which they can do in a heartbeat ...where it would take a US company months or years to implement. Chinese work hard and smart.
The mindset in China is the "we" not the "I" ...as in the west. The goal isn't to sell products for the absolute MOST you can possibly get out of it (like in the west). For many/most of their parts they could charge 5x more and still beat the low prices OEMs are selling. But that's not part of the mindset. Unless you've been there hard to explain. That's one reason they kill us.
I used do do engineering projects with many local manufacturers. I've sat in rooms and listened to owners, or project managers exclaim outright that if they can't make 35%+ margin it's not worth their time (margin...not mark-up) to develop a new product or new model. Stick with the old. And the other mindset of the west that we have to wrestle with, is how companies develop a product and spend untold sums (millions if needed) to sue to protect their patent/profits. That's great, but when someone comes along (like importers) who can do a similar thing for a 20th of yer price, yer in a bind. Whereas in asia (not just China), the emphasis is to continually make it better & cheaper cost. By the time the copy-cat competition catches up, the developing manufacturer (hopefully), is 2 generations newer and better and able to make cheaper. I'm not saying what's right or wrong ...Just some reasons why import parts are a lot cheaper.....