The industrialists tried to coup FDR. They filled the air waves and newspapers with paid opinions about how his pro-labor policy would sink the economy. And then it didn't. Not only did it not sink the economy, it led to arguably the greatest period of middle class prosperity ever seen.
I think there was another small event that occurred around the same time that confounds things a bit. An event which VERY heavily involved industrialists.
Funnily enough, there is a compelling argument that France adopting the 40 hour work week weakened its army and that is what encouraged Hitler to become aggressive. That small event might never have occurred without the 40 hour work week (albeit not the US 40 hour work week that the rest of the discussion is about).
What we do know is that the 40 hour workweek went by the wayside during the war. The US, for example, mandated a minimum wartime workweek of 48 hours in 1943. It would be quite reasonable to conclude that Hitler would have won if labor didn't take the loss. Presumably that is what you are expressing?
I guess what you're struggling to get out is that those sayings were true and thus became adopted as common knowledge? It is the case that people stop talking about things that are already commonly accepted. If it weren't that way we'd be sitting around talking about 1+1=2 all day, every day. It still remains unclear what you think that adds to the discussion, though.
