noticed on my Apple TV there was a new documentary release called "Inequality for all" which features a polished lecture given by professor Robert Reich w/ cool graphics.
Basically it illustrates the gap between rich and poor is at its widest point since the great depression of the 1930's. Its a worthwhile movie IMHO because of its content BUT FWIW I have come to the conclusion that what happened in the USA w/ aviation and the sudden explosion of the US middle class (from 1945 to the late 1960's) was an anomaly in global history.
Before the great depression the way I see things there were lots of poor folk, a small middle class and a much smaller group of really rich folk (which seems to be the historical norm)
IMHO Ford w/ the model T basically stared the consumer society and the "growth" of the US middle class.
Also during this period aviation made great leaps and bounds, starting w/ the first flight in 1903, to the development of the DC-3 in the 1930's which ushered in the era of the airlines which allowed people for the first time in history to be able to visit and transport goods all over the world.
Post WW II is where I feel the myth of the US middle class started. I say this because if you think about it the USA was alone (i.e. w/out "global" competition in the areas of energy production, tech development, banking and the ability to produce consumer goods on a massive scale)
Think about it, up until "peak oil" in the USA in the early 1970's the USA didn't have any global Global competition to speak of in individual areas of energy production, tech development, banking and the ability to produce consumer goods. Granted the USSR was a superpower BUT in military might only. Because the population of the USA was a superpower in all areas, the typical un-educated guy on the street could post WW II expect to have a job that paid an un-imagined high wage (pre-1930's depression) and buy all the products of a consumer society.
In the 1980's japan and germany fully rebuilt their industrial base that was totally destroyed during WW II. During this period the USA was no longer the largest producer of "oil" as a group OPEC because the leading global producer of liquid fuels.
If you look at the problem of why aviation and the US middle class peaked years ago in terms of growth and going from no global competition (1945 to late 1970's) to a global community of players that were able to compete with the USA in individual areas, it seems pretty self evident why we in the USA have a shrinking general aviation population and shrinking USA middle class.