Not a historian, but wasn’t that boom hugely from war profiteering and the fact that none of the bombs went off in the USA? Our factories were all spun up and ready to go while most of Europe was rebuilding. Oh, and the decimation of German and Japanese industrial or technical powers.

But to your point, many graphs showing how much wages have flattened disproportionate to production do show that the period in question was a better time for the average worker.