China would not allow more mercenary to play at its national team anymore. It is a disaster due to the fact that Chinese players don't like foreign players, foreign players have been paid too much and have little incentives to play hard for the Chinese team.
Due to corruption during late 90s and 00s, most Chinese won't allow their children to participate in sport especially football that has more injuries. Unlike Basketball, which parents thought could help their children to grow taller, football doesn't have a good image in China anymore.
Only until late 00s that the number of football players in young children have rebounded. It would take another decade before these children could become more competitive. However, the Super league is in a bad shape right now due to the fact that many property developers have been forced to cut back or exit their spending in football.
Another thing is for many years, the salaries of Chinese football players were very high so they have little incentives to go overseas to compete in more competitive games. So you end up with players that give up the best chance to be a better player and stay home to be an average players.
Personally, I don't care much about football. It isn't important. Military, economy and science should be upmost important for China. Wasting precious resource on football shouldn't be allowed. Any investment in football should be reasonable and sustainable.