Earlier quoted context omitted.
Which is what you would expect, no? I'm not sure what point you are trying to make here, can you elaborate?
Check the percentage of total income vs. percentage of total taxes paid. The system has become more progressive even ignoring the increase in income.
I'm not claiming I know what is actually happening in the US, it's complicated and I haven't spent enough time looking at it to be confident.
However, it's true that if there is a) an increase in total income that b) is entirely captured by a small percentage of people, then naturally their share of the total income tax paid will increase and everyone else's will decrease as a fraction unless the system is regressive in some way.
"Progressive" here doesn't mean higher earners pay more in aggregate, it means (by definition) that their marginal rates are higher that people with lower income.