An analysis based on only WW II and Vietnam (a lost campaign in the ultimately victorious conduct of WW III, a.k.a. the Cold War) is not really very enlightening.
The notion that the general populace of a great power needs to sacrifice to fight a war effectively is not born out by a longer examination of history: Rome's conquests were not accomplished by imposing hardship on the citizens of the Republic. Frederick the Great fought many wars, and only resorted to conscription during the Seven Years War when all of the other continental powers were arrayed against Prussia. He once expressed the desideratum "Ideally my people should not even know that I am at war." Britain's imperial wars in the 18th and 19th centuries were not accompanied by great sacrifice at home, nor by indefinite terms for military service.
Indeed the decisive blows in the Cold War, the arming of proxies in Afghanistan and Nicaragua, the invasion of Grenada (repealing the Brezhnev Doctrine), and defense build-up that the Soviets couldn't outrace (augmented I've heard with faking of greater accuracy than actually achieved in anti-missile tests), were all accomplished without imposing WW II-style rigors on the American people.
What is needed is not hardship, but single-mindedness and resolve, two qualities lacking thanks to the treasonous behavior of the media and the American left both in and out of public office.
However, if I remember correctly, the British used "press gangs" to conscript people during the Napoleonic wars, which were also much like a long world war.
Our "stealth victory" in World War III (the Cold War) was one of our greatest achievements, and kudos go to William Casey, who saw it was possible, and to Ronald Reagan for executing Casey's long term strategy. We were fortunate to be able to do it without firing too many shots after Vietnam.
My point was that during the lifetime of most of us, we have fought under two different paradigms when we were engaged in an actual shooting war. A shooting war appears to be our only choice right now because our enemies have no interest in negotiating or even showing some semblance of reason. The "stealth victory" strategem won't work here. Thus we have to pick a paradigm for a shooting war, and only one has a track record of success.
Most of that stuff was not necessary, at least in America, but was ordered for purposes of civilian morale. It made everyone feel they were part of the war effort, and that every bit helped.
I suppose I was brighter than the average little boy, but even then I understood that Roosevelt was manipulating emotions for propaganda purposes. And I also thought, So what? Our servicemen deserve the moral support."
My uncle, who once came in for a visit and gave me a mesh metal belt he said he had gotten off a dead Jap on the battlefield, with a dagger and sheath, went missing in action in Europe. We all had a personal stake in it and basic patriotism for our country. These little things helped.
Or by a longer examination of the future! Although we are having problems on the ideological front, our long-term military superiority rests on our long-term civilian technology superiority, which comes from allowing the capitalist system to continually exploit the wonders of Moore's and other Laws. If we shut down the civilian economy, we can divert a finite amount of resources to the military for a finite period of time, at the cost of withdrawing from the technology race. In some kinds of crisis this may become necessary, but the current engagement is a multidecade fight against an entrenched ideology. We can't afford to abandon our long-term advantage.
An observation of the American collective psyche would show that when times are tough, when all perceive hardship, Americans are more than capable of pulling together cohesively and cooperatively to 'get the job done'.
In the absence of perceived hardship, of sharing that great collective need to unify against a common enemy who makes its threat felt by all, we all go our merry ways and tend to ignore the existence of a conflict, much less the need to prosecute with equal fervor (if not scale) to that with which we prosecuted WWII.
This is borne out in times of natural disaster as well.
Shared hardship forms a common bond, one which has the capability to transcend almost all other lines along which we fractionate and quibble in easier times.
I guess $3.00 gasoline just wasn't enough...YMMV