As reported by forbes.com: "In the four decades since 1971 the share of the U.S. population earning between two-thirds and twice the national median income has dropped from 61% to 51%." That decline is staggering, especially so in a country that is neither a monarchy nor has hereditary titles, with ostensibly democratic institutions, independent judiciary, and still prides itself on being the land of equal opportunity. According to theguardian.com: "Wealth inequality in the US is at near record levels according to a new study by academics. Over the past three decades, the share of household wealth owned by the top 0.1% has increased from 7% to 22%." This would seem to imply strongly that there is a correlation that as the richest of the rich become wealthier, it has impacted the middle class so that this class is now shrinking at an alarming pace.
There has been a lot of changes in America since 1971, to which some of the most significant, is the rise of technology and robotics, and so too the successful scaling up of so many businesses into truly massive international global enterprises, as well as the unholy alliance that we see so frequently between industry and government, that effectively crowds out other sources and companies that are not part of the privileged set. All of the above, has trickle down effects so that the necessity of your 9-5 worker, has become more interchangeable, than ever before, because as the world has gotten smaller and has reduced or eliminated tariff and trade restrictions, so too job security within industries has definitely gotten more and more problematic.
The biggest corporations in the world are not really interested in employing the most people in the world, gainfully or not, they are far more interested in seeing that they meet or exceed their quarterly numbers, and if in order to do so, this necessitates the removal, dismissal, or replacement of workers, so it will be. To the rich the middle class is like a gigantic mine to be mined until it is depleted and used up, and when finished, they will have the lion's share of the profits and the benefits.
The rich use the middle class in two basic ways. The first is as their beasts of burden, to ride them as long as they have usage for them, and to discard them when their economic utility is less than their output, so as to be displaced with either younger workers at a cheaper wage or even better, with machines. The second way the middle class is used, is to sell them the illusion, that if only if they work a little harder, get their stock options at the right time and price, make the right moves in the right way, that they too can climb up into the rarified airs of staggering wealth. It helps that for the most part, the middle class believes it, but like that carrot on the stick in front of the horse, that keeps the horse going ever forward, the middle class has found over the last few decades, that the brass ring is a game that is often rigged from the outset.
A thing in motion has a tendency to stay in motion, so the rich will continue to get richer, and the middle class will continue to crumble. The rich are not fools, they make sure to provide all the necessary toys and distractions to keep the middle class basically satiated and passive, along with championing any of those few that make the jump into the elite, but no make no mistake about it, the rich only tolerate the middle class because at this time it is more profitable for them to do so. However, their long term interests are direct and to the point, the middle class of America must be eradicated, so that there will simply be those that are privileged, and the balance of the population will be there to serve and to protect their masters from any harm.