Sorry "Your income does the degree of your education?" doesn't make sense. Perhaps you meant "Your income depends on the degree of your education?" Statistically - yes, it does. But some people manage to get very rich with very little education, and some well educated people don't make much money.

Theoretically this is the case, but in the current economic situation it's hard to get a job unless you have a degree where there is a lack of workforce. So despite having several degrees, many people have to take jobs which pay much less.