Earlier quoted context omitted.
If anything, the decline in needing cheap labor is going to be a problem for large countries like China. China needed those cheap labor factories to be the engine to help lift people out of rural poverty. Unfortunately that engine will now falter and many will be left behind. For an eye opening survey here, I highly recommend the book Invisible China.
If they are poorer than people in Vietnam they can just go to Vietnam to work. That's not that much different than going to southern China to work. It is almost a common market.
[0] - https://data.vietnam.opendevelopmentmekong.net/dataset/fefed...
[1] - https://www.rfa.org/english/news/china/workers-1029202011165...