Could that be because the world has changed?
At the end of World War II, the US was pretty much the only industrialized country with its infrastructure intact. This gave the US a HUGE economical advantage and allowed for the boom of the middle class we saw in the 1950s and 1960s. At that time, the US represented a fraction of the world's population but consumed almost 50% of all the world resources. Talk about concentration of wealth. At the time, the US middle class was the world's top 1%.
But the world changed. Not only has Europe rebuilt itself, but more importantly, the 3rd world became industrialized. South Korea, Thailand, China, India, Brazil, South Africa, Turkey, Mexico, Russia, Vietnam all started to produce steel, cars, appliances, machinery, consumer goods and everything else that the entire world had to rely on the US for after world war II. Those countries also started having a middle class and they all started bidding for those world resources that the US middle class before had all for itself. Remember the days when the US middle class was able to afford buying and consuming 50% of the world resources? Well, those days are over, because now they need to outbid the Indian middle class, the Brazilian middle class, the Chinese middle class, etc...They all want a piece of those resources that the US middle class used to consume all by itself. Talk about re-distribution of income! That is one of the main reason why the US middle class is being 'devastated". It is not the only one, but I believe it is one of the most critical reasons. Do you really think it is sustainable and/ fair for a middle class of a single country to consume the majority of the world's resources? That "typical" American middle class that we saw in the 1950s and 1960s was anything but "typical". It was an abnormality created by world war II. And despite all the romanticism and political rhetoric, it is not coming back. The US middle class, the European middle class and the Japanese middle class will have to adjust to a new standard of middle class. A standard that is normalized with the middle class of the emerging 3rd world nations.