US workers get paid more than Chinese ones because they're more productive. As Chinese productivity goes up, so will their wages. Thus, there will be no problem. That, at least, is the simple and short version.
Certain sectors can be disproportionately hurt of course.
Is productivity the only variable in determining real wages or is it even the largest variable? Ideally, it would be....people should get what they pay for....but why get a $900 plasma screen TV when a $50 14 year old 27inch TV at the pawn shop does the job?