[ecnal]

Those articles (and the data behind them) suggest the opposite of your point: the middle class is shrinking, yes, but it's shrinking because incomes are increasing and people who were previously in the middle class are moving into the upper class.

[drawkbox]

Yes and that is welcome, but take another look. They go further to say that since 2000 that trend is no longer a big reason. Even stated in the first paragraph that incomes are falling as the new big reason.

The middle class, if defined as households making between $35,000 and $100,000 a year, shrank in the final decades of the 20th century. For a welcome reason, though: More Americans moved up into what might be considered the upper middle class or the affluent. Since 2000, the middle class has been shrinking for a decidedly more alarming reason: Incomes have fallen.

'67-'99 there weren't stagnant wages as much as post 2000, where we have seen a sideways market, massive recession, 15+ years in horrible economic conditions worsen for lower and middle. Costs rising way faster than wage increases eventually crushes the lower/middle.

The CNN article also mentions money locked up in the upper class and so does an associated video [1]. The lower/middle spend in downturns, the rich do not. Eventually demand is depressed and noone can buy anything. It is bad for lower/middle and upper when noone is gaining in income and has no consumer power gains to grow on. People buy less, people sell less when consumer power is locked up.

For decades, the middle class had been the core of the country. A healthy middle class kept America strong, experts and politicians said. But more recently, these residents have struggled under stagnating wages and soaring costs.

[1] https://www.youtube.com/watch?v=oeCfq-9l_b8 (around :30)