Take a look at this chart from the Pew Research center:
As you can see there the middle income group is shrinking. But look closer. The high income group is growing. From 1971 to 2015 the high income group grew from 4% to 9%. Thats a 5% increase. The middle-high group also grew from 10% to 12% or a 2% increase. On the low end the growth was less. The low income group increased from 16% to 20% for a 4% increase. The upper low group stayed the same at 9%.
Yes the middle class is shrinking. But the good news is that the higher income groups are growing more than the low income group.
Of course its not good news that the low income group increased in the past 5 decades. I had assumed though that all of the erosion of the middle class was putting people into the ranks of the poor. Thats not the case. More than not, people who used to be middle class is migrating upwards.