Deislers thread touches on this subject and how it works (in China). The value of a Chinese player to China vs Europe means there is massive profit to be made by developing them and selling them back (even if they are not too good to be first team regulars here). Also that if we do get a first team Chinese player then the exposure would be massive.
Issues would be, 1) Getting them here as eluded to in other posts (visa etc), 2) backlash from the Chinese league in taking good players that would take away from their homegrown quota and 3) Would be a while until these players are in or around the first team.
Really advise giving Deislers thread a read. The above is me loosely paraphrasing and doesn't do it justice.