They "eliminated" extreme poverty caused by communist control in the first place, by going to a capitalist system.

There were tons of economic low-hanging fruits by building out large infrastructure projects, which corruption happily siphoned off of.

The ROI of these infra projects have been gone for a while, yet they continued. Also it's been stealing intellectual property, trade dumping, exporting deflation. Soaking up the manufacturing oxygen of everyone else through subsidies, elite capture, then using the leverage gained and veiled threats against others to force them to yield resources, market access and political control.