The people who are downvoting my "disagree" are likely assuming that I am speaking philosophically. I'm not. Philosophically, sure: the purpose of the government is to serve the people. A philosophy written specifically for the consumption of people. But now I'm speaking about its practical purpose. What a system produces is always its purpose.
Even with your definition of "What a system produces is always its purpose" is still usually incorrect. The US hasn't "turned a profit" (had a budget surplus) for the majority of the past what, 100 years? Lots of places don't tend to run long-term budget surpluses either. Governments generally don't "turn a profit".
There is no such conscious entity as "the US government". Said entity is a legal vehicle. It can't consciously seek to profit, nor does it care whether or not it profits. However, the point of legal vehicles is to benefit people. My point is that I disagree with the characterization that the primary benefit is "for the people".