What is the general theme of the book Billy Lynn's Long Halftime Walk?

One of the central themes of Billy Lynn's Long Halftime Walk is concerned with the stark difference between the life of Billy, who is from Texas, and the lives of the wealthy owners of the Dallas Cowboys football stadium, with whom he meets during a victory tour he is on across the US. Billy is part of Bravo Company, which is stationed in Iraq. His world revolves around the values of freedom, democracy, and the American way of life.
Meanwhile, the owners of the Cowboys speak the language of finance and in terms that he does not understand. However, he is clearly impressed and hopes to one day become as wealthy and powerful as they are. Billy becomes transfixed by the notion of being able to do something like "leverage his assets" in his quest to become financially successful. On the other hand, he is determined not to fall into the debt traps that many people face over the course of their lives.