Not all are destined to be very rich. Even if you work harder than anyone else, I think luck and knowledge are still to be considered. In my country, those at farm fields planting rice and stuffs are the most hardworking yet they are considered as a Poor Class having less than 200$ a month. To be rich needs knowledge, dedication and the will power to learn more everyday until this knowledge produce ideas that could lead to passive income.
All jobs have positive and negative sides, don't look at a job only from the negative side. a farmer does have a small income but they can manage their time easily while those who work in a company have a higher salary but they are not free to manage their time because they are tied to work. on the other hand not all farmers have a small income because many people become rich from farming.