The same mistake has much worse consequences if you don't have wealth.
The poor people who burn out completely and stop working end up on the street and either die pretty fast or find some more motivation to keep going even in that state.
Also, sadly what many poor people lack is not work ethic but capital, in the sense that they can't just take on a ~20-30M loan to send their kids to school and wait for them to start working and then pay it back. So instead of doing this they are forced to do very near-zero ROI things.
If anything, it's easier to go from having nothing to a comfortable, middle-class lifestyle than it is to go from middle-class to wealthy.
I guess people who live in the third world and have mastered English see living proof every day of where their hard work can get them.