You are comparing the first world with the third world.

The difference is not that big, at least not 2-world big. The difference is much smaller that 10, 20 years ago, and will be smaller and smaller.

20 years ago, in China, city residents had average 3 square meter house/person, no personal car, no hot shower at home.

25 years ago, China city residents got 0.75 kg meat a month.

I would say China made big improvement at last 25 years, much faster than US.