The problem in this case, I think is economies of scale. Rather, lack of. Usually companies would like to increase their output to fulfil demand and at the same time reduce marginal cost. The problem here, is that the concert cannot be moved to a larger venue. The demand is simply too large.
Crude Example:
In a city of say 9 million people, such as Greater London , a large concert venue will typically have 50,000 seats. This represents 0.55% of the people. And we can use this percentage as a rough indicator of demand.
In a city of 30 million people such as Beijing, assuming 0.55% of people also want to visit the concert, this would equate to 165,000 people. Of course, without increasing the size of the venue by a factor of 3, the price would have to increase to reduce demand down to around 55,000.
Concerts are considered a non-essential luxury, which normally would be considered price elastic. But since they are still rare occurrences and there are few opportunities to attend the same concert again in the near future, there are no close substitutes. This would mean concerts are actually price inelastic. For the demand to drop, there would have to be a higher percentage change in price.
This is why I think concerts in China cost more. Not because of lack of free market competition, but rather the free market itself which determines the price of the tickets due to China's unique people and scaling problem.
You posit that problem is the demand is greater than the supply of seats, because of the scaling of the venue required. But I am wondering why can't more stadiums be built so that more concerts can be held, so as to spread the demand over more seats per unit time. The Chinese have never seen an infrastructure project they didn't want to finance.
One possibility is that certain concert artists are in higher demand (e.g. status symbol to attend their concerts), and those artists only want to play a limited number of concerts, thus larger venues would be needed to spread demand over a larger number of seats. The other possibility remains my original hypothesis of corruption and captured markets. I would bet it is skillful combination of the two, expertly hiding corruption behind natural human tendency to follow each other likes ducks to their idols. Thank you for pointing out the factor I missed, which is how the density of the population impacts the demand per seat. I remain quite skeptical there are totally free markets in China.
Edit: another possibility is I guess that density of buildings in the city make it expensive to build additional venues within reasonable travel time+cost for majority of inhabitants. But given how much investment China has put into affordable public transportation, this seems less likely to be the issue. I would think people would travel an hour to have affordable ticket prices?
In general, Chinese seem to favor status symbols, i.e. the organization of society where some symbols of status are only available to those of greater means. The recent 2014 CIA Gini coefficient and the R/P putting China at 28th worst in the world, in dangerous trajectory of African banana republics (given the Gini increased from UN 37% estimate in 2011).
Is there something in Chinese culture that favors emperors? I have read one of the Bitcoin Chinese mining cartel state that Chinese prefer top-down organization and "might makes right".
I personally have always had a lingering bad taste in my mouth from at least twice being rejected by Chinese due to their status symbol culture. First was in my 20s in Los Angeles when I entered an all-Chinese disco bar and tried to socialize. Everyone refused to even make eye contact with me when I spoke to them. And recently in Hong Kong, where none of the workout gyms in Kowloon would allow me to pay for a daily workout. You had to be a member which required an introduction from other member, i.e. non-Chinese were not welcome. Even the upscale hotels with gyms wouldn't allow me to pay for a workout, unless I booked one of their exorbitantly priced rooms.