The fallacy is that you don't know, can't know, what our economy would have been after that period, absent WWII. What if we were on the cusp of recovery anyway and we had spent 5 years building railroad and machinery rather than tanks and bombs? The end result would have been a more efficient application of industry over time, resulting in a more abundant society, right?
But I can't say that was the case, would have been the case, any more than you can say the opposite, because we don't know what would have happened if we had tweaked x or y, and can't test it. That's why economics is a social science, not a science. That's why economists are still arguing over what caused the great depression, as well as what ended it.
It's not a fallacy because I specifically pointed that out. You can, however, point to all of the various technologies and cultural shifts that impacted our economy, and the 50+ year period of unrivaled prosperity that occurred afterward and say it most likely was for the best.
Very few nations ever achieve a period like America did from that point to probably about 9/11/01. If we had to make the decision again from a purely economic standpoint, given the benefit of hindsight, we'd make it the same way.
You did state rather unequivocally that WWII fixed the economy:
> It didn't suffer through it at all, it got fixed by it.
And now, you're attempting to declare post hoc, ergo propter hoc? The whole point of what I'm saying is that there are thousands or millions of changes in policy, technology, demographics, sentiment, which had an impact on the economy, we don't know which did what.
I could just as easily explain the post-war years by saying that it's natural that any country which does not get bombed to smithereens will experience relative prosperity, whether or not it participated in bombing other countries, as we did in WWII. Perhaps it was only that advantage which overwhelmed the tax of war spending.
Again, I can't say for sure, but neither can you. I'm inclined to think you're wrong though, from the simple perspective the the allocation of resources over time.
But I can't say that was the case, would have been the case, any more than you can say the opposite, because we don't know what would have happened if we had tweaked x or y, and can't test it. That's why economics is a social science, not a science. That's why economists are still arguing over what caused the great depression, as well as what ended it.