That has improved and continues to improve over the last several decades, and the wealth disparity is a whole order of magnitude less than the U.S.
Billionaires in China are rich in name only. The only things they can get with money are a slightly fancier car and house, they aren't able to buy elections.
The wealth disparity has been roughly the same for the last 20 years...
China is an authoritarian one party state. There are not really elections to buy. And you would be daft to think a Chinese billionaire can only buy a slightly better house.