This is a huge change from what the country was once like, when it had a robust middle class.
First of all, this is the norm among industrialized economies. Perhaps Norway is different. I haven't checked since the fracking boom.
Second, the thriving middle class was a fairly short lived affair, centered around three decades from 1950–1980. Most affluent societies have now returned to pre-1930s levels of economic inequality. Historically, an affluent middle class is the exception and not the norm.
I had a college roommate whose brawny younger brother dropped out of high school with few skills and somehow got a job with the CAW at a starting wage north of $70,000 per year, back in the early 1980s. He soon had a wife and children, a driveway filled with expensive motor toys, and cash-flow problems.
He was almost certainly employed at a factory making automotive products that discerning consumers—those of us lacking misty-eyed Big Three loyalty—did not wish to purchase.
Meanwhile, high school drop-outs trying to scrape by on non-union wages weren't necessarily doing much better than those same people today, a major difference being that the majority of those fantasy union jobs have now gone away.
Someone needs to get in a time travel booth to go back to the early 1970s to inform the CAW management group that no matter what course of action they chose, their business model (high union wages for semi-skilled labour) could not survive selling shit product. Marketing the hell out shit product was a short-term solution at best (Future Shop—ultimately—not excepted).
As much as the Reagan and Thatcher plutocrats initiated a self-serving destruction of the middle class, the middle class itself was hardly blameless.
Now it's time for the plutocrats to determine whether they can recognize how they are painting themselves into a non-viable corner before they encounter a messy corrective force of their own seeding.