Labor and Luddism
It can be read a metaphor for the fall of the American labor base. Gru's operation makes heavy use of labor, and his style is straight out of the 1950s—the high point of labor in America. The villain, Vector, is an entrepreneur who has zero employees and even looks a bit like Bill Gates◊. The story is a fantasy wherein the American manufacturing sector rehires all of those blue-collar pink-slipped workers who got laid off in the 1980s, and all the automation and offshoring just goes away.