The only valid information we can derive from simply comparing wages across the world is the indication of each regional economic level. That's all. A specific wage number from one economy can only be assessed as fair (or not) by knowing where it stands relative to cost of living in the same region.
The flight of manufacturing from the U.S. to China was only possible because multi-national corporations could have the work done in China at much lower wages - then ship to consumers in America to purchase "at a bargain." The profits were huge. Like I stated before, when the U.S. economy was drained of enough jobs at reasonable wages, the profit system collapsed because that cycle was broken.
Over two decades, that event put more stress on our economy forcing more people to demand lower priced basic products. They had no choice. One consequence was that our government grew to unsustainable levels in an attempt to keep people from becoming homeless and starving - and at the same time catered to mega-business to keep the political funding coming into congressional campaigns. The result has been the slow and painful elimination of the middle-class. One of the major corporate CEO's lamented in a televised discussion of executives that his greatest career mistake was in not understanding the value of the American middle-class (in this context, it's all workers with an income large enough to keep them from requiring financial assistance, up to $250,000/family).
Credit has done more damage to the economy than all other factors combined.