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