New York is #3.
Connecticut is and exception at #23, but I wouldn't be surprised if a lot of it is finance commuters from Wall St. In New York.
While there are exceptions, that list seems to correlate pretty well with the list of states ranked by GDP.
While probably intentionally non committal, I think your post is still a bit misleading.
Do you mean median income?
vs
Progressive taxation causes income inequality
I don't see a reason to say it should be frozen in time at whatever level it was in 1978 or progress to a utopia where every single person earns the same (or where every X percentile of people owns exactly X percent of the wealth).
This isn't to say that the current system is helping people, but pointing at this particular chart doesn't seem to do any justice to the idea of why life might be worse for the average US citizen. We could just as well reverse course and have a chart where income tends toward total "equality" and still make the world a living hell. I believe in our ability to do that.