I don't know about the average "industrial wage", but that sounds like a bad metric to focus on. Manufacturing in the US has dropped from around 25% during this time down into the single digits, so it's not as common a job as it used to be. If anything I'd expect the wage to have gone up, since those jobs are now more specialized.
You'd think so, wouldn't you? The truth of the matter is most manufacturing companies are facing the same problem tech is right now: a "talent" shortage. The pay hasn't kept up with living costs in most areas. The days of buying a house and raising a family on an "industrial wage" are long gone. The pay is hardly enough to keep one person alive these days. As a result, nobody wants the jobs. The companies can't keep their assembly lines fully staffed, but they don't want to pay more either.
What I do know is that the average industrial wage relative to the cost of living has been steadily declining with a marked plunge from the 80s onwards.
I will concede that the 50s is a poor comparison, as much of the western world was in the midst of a post-war economic boom at that time.