This article isn't really arguing what you're arguing though. Productivity (in the US specifically) has continued to grow at a brisk pace, but wages have not. This does not mean that the US has slowed its ascent, and the third world has begun to eat into that productivity; it means that, as wages stagnate, this increased wealth is captured more and more by the top level, the businesses and owners.

If third world countries were eating into this wealth, you would see the entire pie shrinking. As it is, the pie is growing larger, but all that growth is going to the rich owners, and none of it to the workers.