So all of these millions of people in America each, independently, just made the same bad choices when it came to their finances, and there was no economic driver for that happening except, what, stupidity?
No. Wealth distribution is measurable, and has clearly become increasingly skewed since 1980. To suggest that wealth being transferred from the lower classes to the top 20% has no effect on the populace’s marginal propensity to save, well I would have to see very compelling evidence to prove that.