On a positive note: those Nukes are probably what has stood between many state v state wars which may have taken place over the past 60 years had the assured destruction not been there.
You seem to forget that wars are expensive, very expensive. The US was already running bankrupt before the end of WW2, nobody in any sane state of mind wants an all out war unless they can avoid to do so.
Germans were starving to death in 1946; Brits were still rationing meat and food in 1954, and cheese for decades to come.
Wars are not in general good for the economy: they result in the destruction of capital and of labour.
As you said it did not suffer any damage to its industry and took over from Britain, France and Japan as the imperial power in the Middle East and Asia.
There have been plenty of conventional land wars in the following years with US involvement, the difference was that while WWII was fought to establish large American spheres of influence, the following wars were fought been to maintain the American empire.
It is pretty hard to quantify, but I'm confident that people in power thought that the net benefit of maintaining hegemony in South East Asia (Korean/Vietnam war) and the Middle East (financing Israel, the Iraq wars), outweighed the cost.