It may be that PVG/PEK and possibly CAN are seen as the main airports, after all, it's where the majority of long haul goes into.
Xi'an, Chongqing, Changsha, Wuhan and the likes, while they do have some long haul, are not seen as the main entry points.
I suppose it's like the UK, LHR is seen as the primary point, and as no where else comes close for the level of long haul, everywhere else is secondary. This of course is my interpretation and opinion, but, I believe it to be accurate. Just because MAN does well with long haul, doesn't mean it should be on the same pedestal of London. It's simply unrealistic.