It's absolutely propaganda. China's GDP per capita is around $15k while the US's is around $60k; China still has a long long way to go, decades at best, before the average Chinese person's standard of living is comparable to the average American's. And given the population aging/low birthrate problem is even worse in China than in the US, it's going to be a struggle to get there.

China simply has a population around 4x larger than America's, so even at a much lower level of development/standard of living it can still have a very big impact on the overall global economy.