In some cases, yes. But I think on balance people who escape the countryside for the city factory jobs are not leaving a comfortable job for the promise of riches but with health risks. The factory/city job offers a much better alternative. An alternative to being a subsistence farmer or a day laborer, or a maid, or the daughter who has to marry at 16-18 and have no chance at an education. In the countryside it's not unusual for people to barely 'eke out' a 'living'. It could be picking up discarded trash and finding something recyclable, etc. Going from the coutryside to working for a Foxconn is like going from line cook at MickeyD's to being exempt salaried in the US with flex time -it's no contest.

As 'unhealthy' as the city job might be, the alternative in the countryside is, for many people, worse. It's a life of a kind of feudalism.