Although members of the military recognize the shift, it is seldom acknowledged by the civilian command structure. Even those who understand generally assume that greater US resources and wealth make up for the cost disparity.
In football or basketball, if your team has the ball, you are the offense. In warfare, if you are in another country, you are the offense. An invasion, difficult as it may be, is invariably the easy part. Anyone who knew military history winced when President George W. Bush gave his 2003 Iraq victory speech, Mission Accomplished banner stretched behind him on an upper deck of an aircraft carrier. If, to give the neoconservatives their stated case, the mission was to convert Iraq to a thriving, peaceful, multicultural democracy, fourteen years later that mission remains unaccomplished, the prospect just as remote as it was before the US invaded Iraq and deposed Saddam Hussein.
The US "victory" in Iraq created winners and losers. Previously marginalized Shiites who formed the new government were the winners. Ousted Sunni Ba'athists who had stocked Hussein's government and military were the losers, and set about upending the new order. In their war against the US and its newly installed Iraqi government, they had every advantage defenders have playing on their home territory. They knew the territory and the language, drew on local Sunni support, blended in with the "civilian" population, and used women and children operationally, pages straight from the Viet Cong playbook.