Travel to China is highly regulated and even air fares are regulated, so LCCs are currently given the shaft.
I travel many times to China/Japan and flights of only 1.5 hour duration can cost upwards of US$2,000 on full-fare with only modest or negligible discounts on routes where there is no competition.
Japan to Shanghai routes are less expensive because of the larger number of flights but they are still not exactly inexpensive either. This is one the big reason why the Japanese legacies are making money even with poor loads because the yield is so high.
Japan is so much more different than the US or Europe because of the lack of a secondary airports to the main cities such as Tokyo & Osaka. First problem is slots at these airport and then the development of the secondary airports is out of the question because there aren't any to speak thereof and not likely to change anytime in the next decade.
Lastly, the reason is user fees more than anything else that drives up the cost of doing business in Japan. Whether they be enroute, landing, parking, etc, the Japanese Ministry of Transport charges a lot and then there's all the bureaucracy attached as well.
As a personal opinion, I could care less about LCCs, as fares are not exactly dirt cheap but no longer that expensive in previous years on domestic routes. In the last decades, there are a variety of air fares based on advanced purchasing introduced. While there maybe some downgauging in aircraft size as HND
opens up another runway, I would much prefer a 777/787 flight to any narrowbody flight regardless of the duration of the flight. Next, I'd like to keep the RJ
phenomena (except where necessary) out of this neck of the woods.