That argument is brought up often by those who would dismiss an American insurgency. Here is the question I always ask in response. Who is it that sends their kids into the military? It isn't the upper class globalists in urban centers, it is mostly the urban poor or the rural folks. Like I said before, there is a significant amount of active duty personnel who take their oath seriously. Do you really think Johnboy is gonna go confiscate guns from his family and neighbors or people like them? Or maybe, he just might leave and take some tech with him. A group of college kids recently proved how easy it was to seize control of a drone with equipment bought at radio shack. Seize them if you can, crash them if you can't.
And to be perfectly blunt, the last 11 years have explicitly demonstrated once again that insurgencies work. What we have in both Iraq and Afghanistan are political exits, not true military victories (admittedly, we never had solid objectives in either conflict, the goalposts kept moving).