Is the U.S. income gap holding back economy?

I think too much emphasis is being placed on the income gap WITHIN America, and not enough on the income gap between America and the rest of the world. The same people who decry "corporate greed" will also complain about off-shoring jobs to 2nd-3rd world countries who desperately need to raise their standard of living to at least a level we would consider lower class here in the USA.