Not everyone can be in the position to make the kind of sacrifices needed for great monetary success. A family man or woman has to think of the family first, especially if it is a large family. In fact those who do make it big usually start early before marriage and also after marriage only have a few offspring.
Then there is education. Always to be reviewed in two parts. There is street-wise. Those who can read people well or learn to read them well can have great success with very little formal education. Street-wise education for most people, however, consists of a lot of hard knocks before you figure out what information from the street works best for you. Yes. There is working and working smart. It isn't always easy to tell the difference. Sometimes working harder than most still isn't working smart. A lot of people don't get that.
Formal education is not that easy to come by in the USA. As in Australia a lot of High Schools (or I should say the American equivalent) have difficulty with students who have English as a second language and of course you have students who battle to come to grips with English as it is their secondary language. Result? There can be and too often are social divides thus created. Part of the answer of course is the employment of more teachers that are great with more than one language. Finding said teachers isn't always an easy task for an education department. Also there are parts of the USA that have reverted to gangland mentality and once you are in a gang you are basically cut off from the rest of society and your future is bleaker than it might otherwise be.
It is not easy to get into college or university in either the USA or Australia and usually there is a debt hanging over the person that must eventually be paid.
Health is another issue. The health system in the USA is not very good. Sick or injured people who cannot get medical help are not likely to be big future money makers. Unfortunately there are people in Australia that want the Australian public to go down the American path.
And so if you can be street-smart, formerly well educated and have some start money you are very lucky. You might just become rich if your luck holds out and you don't go under when the next financial wave of disaster hits the western world.