I suspect that if you fly on Chinese carriers such as MU and CZ, there are lots of fares to various places in Asia with connections through CAN, PVG, or PEK. For example, if you want to fly on MU, LAX-PVG-TYO would be a reasonable/logical routing. I'm not sure the extent to which you can now easily integrate these intraAsia flights using partner Chinese carriers with TPAC flights on USA legacy carriers to get a ticket to Japan, Korea, etc. that connects through mainland China.