The gap is shrinking? Who’s catching up? It’s ludicrous to say we don’t have the firepower to win a full scale war. We do, and we’re not in one at the moment. Counterinsurgency is not what the Army is built to do at the moment. The way o free up manpower is to ditch the Cold War setup and reorganize into smaller, lighter units. Which Rumsfeld was doing.
What would count as a coalition of some significance? We had Britain and Australia, plus smaller contingents from dozens of countries. Who’s missing that would make it ‘significant’? Aren’t you ashamed of your arrogance calling a coalition of two UN Security Council members plus dozens of other sovereign states insignificant?
Was the war against Japan a failure? That was the US, UK, and Australia as well.