According to fred.stlouisfed.org, in the 3rd Quarter of 2017, personal consumption expenditures as a percentage of our Gross Domestic Product (GDP) stood at 68.866%, which signifies that more than two-thirds of our economic growth comes from the consumers of products here in the United States. This percentage of personal consumption expenditure has inexorably grown over the decades, as demonstrated by the fact that in the 3rd quarter of 1963, it was at 59.818%. However, there is a fundamental difference between such expenditures back in 1963 and expenditures today, which is that the sheer amount of indebtedness of Americans has skyrocketed since then, and there most definitely comes the point when such debt reaches its limits and has a material effect upon further expenditures, and/or becomes so large as to become unstable for consumers in being able to stay current on such debt and therefore to continue successfully servicing such debt into the foreseeable future.
While one can certainly say that Americans like to shop and to spend, the problem is that the wealth of this nation is so extreme, signifying that the most basic issue when it comes to our Gross Domestic Product is that while the poor would love to spend much more money on goods and services, they don't have much money or borrowing power to spend, and whereas the rich have plenty of money to spend, there are only so many houses, cars, and other assorted goods that they desire to purchase, before setting aside the bulk of their wealth into investments and thereby making more money from having money; this, then, leaves the middle class, which Pew Research Center indicated in a recent study from 2000 through 2014, that the middle-income households declined by 4% during this period, yet, their overall indebtedness for such middle-income households increased. Never have so many had so much debt through mortgages, credit card loans, automobile loans, and student loans, so that as reported by the fool.com, "As of 2013, the debt burden of the average middle-class household stood at 122% of annual household income." This sort of indebtedness in an era of historically low interest rates for debt, signifies that should interest rates normalize or increase over the coming months and years, in which governmental officials have indicated that they will, that those suffering from such debt, will have even more of a debt load burden to contend with, which, logically would mean, that a drop in personal consumption expenditures would occur, creating or exacerbating a recessionary environment, made even worse if those issuing such loans were to withdraw or withhold the punch bowl of even further debt.
The middle class of this nation is the fulcrum upon which continuous growth and prosperity lie, and this middle class is suffering from a reduction in numbers, an economic stagnation or regression in wages, and a personal debt level at historic or near-historic highs, signifying that if the middle class is "tapped out" that national personal consumption expenditures must fall. This so does indicate that the distribution of wealth, and the collective income of nations, most definitely makes a difference to the overall prosperity of a nation, and when such distribution puts more and more money into the hands of the superrich, eviscerates the middle class, and leaves the poor as a permanent underclass to be a lifelong burden upon the government, than the end result can only be ruinous, for the middle class truly is the engine that keeps growth going in this country on a positive basis, and when they no longer have the wherewithal to do more, it will collapse.