In 2000, economist Steven Levitt and sociologist Sudhir Venkatesh published an article in the Quarterly Journal of Economics about the internal wage structure of a Chicago drug gang. This piece would later serve as a basis for a chapter in Levitt’s (and Dubner’s) best seller Freakonomics.  The title of the chapter, “Why drug dealers still live with their moms”, was based on the finding that the income distribution within gangs was extremely skewed in favor of those at the top, while the rank-and-file street sellers earned even less than employees in legitimate low-skilled activities, let’s say at McDonald’s. They calculated 3.30 dollars as the hourly rate, that is, well below a living wage (that’s why they still live with their moms). 
If you take into account the risk of being shot by rival gangs, ending up in jail or being beaten up by your own hierarchy, you might wonder why anybody would work for such a low wage and at such dreadful working conditions instead of seeking employment at Mc Donalds. Yet, gangs have no real difficulty in recruiting new members. The reason for this is that the prospect of future wealth, rather than current income and working conditions, is the main driver for people to stay in the business: low-level drug sellers forgo current income for (uncertain) future wealth. Rank-and file members are ready to face this risk to try to make it to the top, where life is good and money is flowing. It is very unlikely that they will make it (their mortality rate is insanely high, by the way) but they’re ready to “get rich or die trying”.