Many subjects relevant to life and living are not taught in school. One of them is How to Get Rich ?
When you work for someone else, your salary is determined by that person; a portion of that salary will have to be used to pay annual taxes, another for rent, and another still for transportation and yet another for daily expenses. Eventually, you will he left with just enough for your food for the month.
Entrepreneurs, on the other hand think for themselves. They learn to maximize their manpower or facilities while they supervise to gain income from the work done by others, and enjoy the profits that this brings in. They work to build wealth and not just to earn an income.