Several years ago,  I had numerous conversations with manufacturers via Alibaba regarding Carbon rims.   From my perspective, carbon rim manufacturing in China is now a commodity product.  China has several holding companies that are dedicated to engineering,  designing and manufacturing the tooling and molds necessary to lay up and build carbon rims.  For a new company wanting to fabricate carbon rims, the barrier of entry is relatively low.  A new company can also contract with rim foundries that make rims and have their specified rims made for them.

YISHUNBIKE is one example of a company that specifically manufactures carbon rims for wholesalers. 
I believe that the majority of carbon rims sold in "Stores" in Aliexpress are selling rims fabricated in the rim foundries.

Regarding bicycle frames,  Manufacturing technology for carbon frames is still advancing.  Carbon frame manufacturing is a lot more complex than carbon rims.  Over time, there has been a convergence of manufacturing practices that is making it more efficient and easier to make carbon frame.   (Think open mold frames.)   
Optimizing frames for minimal weight, durability and cost is still very time consuming and expensive.  Most Chinese carbon frame manufacturers, higher end frames are in the 80% range for weight,durability and cost.   China tends to lag behind a couple years in the latest fabrication processes that the high end frame manufacturers utilize.