A person's income is not measured by how high their education is, but how persistent they are in trying, people who are persistent and never give up will get results commensurate with their struggle, many people are smart in education but they are picky in work, but people who are low education will take all the work as long as they can make money, that way they will continue to learn about how to make more money, and they always try continuously until they reach the point where they want, in terms of education alone it cannot measure like other people that is being persistent in fighting for success, in the world of commerce what is important is being persistent in trying, never giving up, failing, trying again, falling and getting up again, that is the key to success for someone who is active in trying.
This is so true, I have seen a lot of practical examples of this in my life where people with very high education and knowledge are working for small wages while those with less education but smart mindsets and quick thinking abilities are running businesses and companies. The reason is the struggle they do and the amount of dedication they put in each work that they get into.
Many people wouldn't take their jobs or businesses seriously, many lose their jobs or businesses because they are overconfident. It's good to be confident when you are doing well, but a person needs to stay low all the time, evaluate every situation and see what's happening around no matter how high of a place you have reached.
So it's all about the mindset of a person, in my opinion.