I think the cause is relying too much on muscles. From several places I have seen, a farmer can reap many times the profits from his harvest. The problem is they are reluctant to leave the situation, even though if they are willing to set aside a little money to say invest, I think they will get out of that zone.
Then the profits from the harvest are used for farming again and usually the results obtained are actually a loss, it could be due to falling prices or being exposed to pests. And so on.
So as long as they're still using the same pattern it's a bit difficult for them to get more results than they did.
Anytime a person starts to question the individual instead of the system when there are millions of people who are underpaid, that person needs to look in the mirror and ask "what is wrong with me?". We are living in a world where whole nations are poor, we are talking about probably billions living under threat of starvation (some actually do starve to death) and you are talking about "there are better possibilities but they do not take it" to individuals.
It is the system that is obviously wrong, most of the time when I talk like this people assume that I am trying to bring the socialist agenda to help out everyone, but the ideas of socialism would never work in these type of governments neither, it is quite horrible to be fair to give governments money considering how they inefficiently use it, but the liberal ideas also starve people to death in order get mega yacths.
So, what is correct way to have a base of "shelter, food, clothes, health, education guaranteed, but there will still be billionaires" type of situation? I do not know, Europe seems to be doing better than most of the world, maybe we should look at them.