What is an employee worth, as an economic unit? In the absence of a labor shortage or non-economic forces, it's just maintenance and education cost. A dorm in Shentzen, some food, and training programs. The maintenance cost on humans hasn't increased much in recent years. Why should wages ever go up?

Rising wages means that people are being paid more than they're worth as an economic unit. Unless you're willing to take the position that people should be paid more than they're worth, you can't expect wages to rise.

Unions once explicitly took that position. A century ago, when Samuel Gompers was asked what he wanted for his union members, he answered "More". That's really what unions are for. In the 1950s and 1960s, not only did unions take that position, many manufacturing companies had come around to agree with it. It was a basic bargaining position in UAW negotiations of that era that wages must rise with productivity. The auto companies went along with this. That drove wages up across the US.

That ended in the 1970s. It was the result of explicit policy decisions.[1] Ronald Reagan is called the "Great Communicator" because he was able to sell some of those policies.

[1] http://www.h-net.org/reviews/showrev.php?id=35277