Important in this ideology is that flying a boeing into a building and killing 3000 people is not bringing war to your doorstep.
Furthermore, this is a bit of a counterfactual as we don't actually know the trajectory of technology without the war. Some thing we know for certain though, mass electrification and public health were well underway before the war and continued through it. These being probably the two most important developments that improved productivity and the quality of life for most people.
People who fought in and justified WWII contrasted it with WWI. The claim being that WWI was a war fought on behalf of the old world system. And WWII was a true war for Democracy. I think it would've been very hard after that kind of mobilization, sacrifice and rhetoric to re-instute the Gilded Age ethos of a system which the rules of the game were sacred about the outcomes.
In this way American Democracy is born of the FDR era. I don't mean this in the narrow sense of the size of the electorate though that is important. At every level, America's systems Democratized. From the way the Supreme Court interpreted the law, to the choices of industry in what to produce, to how the rewards of production were distributed. There was a broad transition from the notion that institutions existed to maintain rules towards a notion that these institutions in their largest sense needed to serve the people.
I think a lot of what has happened since 1970 is a transition back to a way of looking at the world through the pre-democratic lense. The biggest difference being that now there is a plurality which is the upper half of the middle class who have some similar interests to the wealthy in protecting their wealth.
I agree although I believe that the upper middle class and the capital class still don't actually have similar interests if you think about things that are actually in the upper middle class's best interest. In the context of a propaganda model (1), most people just aren't exposed to opinions that even align with their true economic interests. They are often exposed to opinions that actually kowtow the economic status quo that benefits the existing elite establishment more than anything. Mass media has been able to stratify labor: it has divided the working poor among right and left on cultural considerations versus unifying it through economic arguments, and made the white collar class which still has to sell their labor for wages believe they are no longer of the working class, and have little need to organize themselves. Labor as a unified movement has been divided and effectively conquered. A sad state of affairs.