This work is based on a response to a question answered on Quora. It has been modified in wording somewhat. That post is found here:
You occasionally hear people pontificate that war causes rapid technological advance
I profoundly disagree with that position Yes many military technologies were developed, but underlaying industrial technology that is the foundation of all technology advanced little compared to what it might have, add to that the dead and wrecked infrastructure, and very definitly in the net the war was a loss.
Also publication of many scientific, mathematical, technical and engineering journals largely stopped for the duration of the war, and even longer for many areas of physics related to nuclear studies.
Numerous technical professionals were killed, or so badly injured they could not work, during the war from all countries.
When you ask “what were the benifits” you leave unsaid “benifits to whom”.
https://en.m.wikipedia.org/wiki/World_War_II
https://en.m.wikipedia.org/wiki/World_War_II_casualties
WWII cost approximatly 70 to 85 million human lives.
The aftermath of WWII of communist assimilation of Eastern Europe and China cost an additional ~ 80 million lives.
https://www.hawaii.edu/powerkills/20TH.HTM
Total cost of the war and the political aftermath ~ 150 million human lives. The economic costs of the war and it’s aftermath were also immense and hard to be calculated.
No one nation “won” WWII, not in the sense of having gained economically. The USA who was closest to “winning” WWII in an “economic sense”, lost 407 thousand military dead, approximatly 12 thousand civilian dead. The economic cost of the war to the USA was about 3.58 Trillion in 2005 US dollars.
https://caseagainstbush.blogspot.com/2005/04/financial-cost-of-world-war-ii1u.html?m=1
The worse thing to the USA after the war is that our defense and other costs went way up a lot. We went into a cold war with the USSR and the Communist International that cost quite a bit more than the war did long term.
Going back to the “benifits to whom” question, the only large group that net benefited from WWII was the Communist International. By the end of the war, in addition to what they controlled before the war, they picked up most of Eastern Europe including about half of Germany, Manchuria, Northern Korea, and Northern Vietnam. By 1950 they had all of mainland China too. A clear net gain in territory for them that presented the USA and western nations with serious security issues.
We can also agree that a small number of industrialists in the US and British Arms industry benifited financially, but that was not a significant sized group, and they did not start the war, nor participate in starting it. The communists took part in the attack on Poland that set off the war in Europe, and communists participated in the Chinese -Japanese war against both the Chinese Nationalists and Japanese making a diplomatic solution hard.
Other than the communists as an organization, and a few industrialists, the evidence is no nation or other large group net benefitted from WWII.
Even if they did, the cost of 160 odd million human lives clearly establishes the “benifits” in technology of a few years earlier than it would have in an alternative time line where WWII did not happen, cannot possibly be worth 160 million lives, let alone the economic costs.
To me this question seems offensive and thoughtless to the loss of life.
War is not a benifit, sometimes it is necessary to fight a war against an aggressor, but if it gets to the point that the bullets are flying, the statesmen and diplomats have screwed up, badly.