We are falling behind rapidly. Here is a small example: My niece ordered an Android cell phone cover for $8 from China. It was supposed to take a month for delivery. She got it in a week with freebies for extra credit. She lives in Florida.
A lot of people have been kicking around that story for a while, and depending on which currency conversion used some say China's already bigger. Back in the early 1950's America's gdp was more than half the world's total and now we're "only" about 30%; somehow I don't see how being richer is a bad thing if others get rich too.