The "dark" EV plants making cars aren't using any labour, let alone cheap labour.
There's also that thing that made China what it is today - the USofA using China for cheap labour and a place to outsource all the dirty parts of high consumption.
The US doesn't have those because we're not even trying.
China is capable of it due to the absolutely brutal grinding work culture. They're not superhuman, it's not Tony Stark building the Iron Man suit in an evening, they're smart and work extremely hard.