The answer is right there in the article: offshoring. Post-war US had close to zero economical competition for a few decades. Which is exactly the time where y

The answer is right there in the article: offshoring. Post-war US had close to zero economical competition for a few decades. Which is exactly the time where your grandparents and parents spent most of their adult lives in. Middle class on easy mode, a simple job supports an entire family. What changed is that the rest of the world caught up. Middle class on easy mode was a blip, not a permanent standard. What the west lost, the developing countries gained. There's of course secondary factors too: different demographics (more workers, less elderly), women were not in the work force making labor more scarce, work was more stable and not constantly technically disrupted, etc. It's complicated, but the idea that uneducated labor can support a middle class family is not coming back, ever.