a manufacturing robot(in 2014,not a very recent fig but good reference)

https://ark-invest.com/articles/analyst-research/robots-will-save-manufacturing-billions/

"Robots also have operations and maintenance costs which we calculate at approximately $10,000 annually.."

A bot like that can replace 4 workers@ annual pay $2500/yr or $210/month(+ some inflation)

likely the kind of wage in VN but already exceeded by those in china.

A.I. and robotics are the way to go for China