For example, my Dad had only one dial phone in the house. So I guess that makes him "poor" and me "rich" because by age 40 I had cell phones, a landline, cable television, and high-speed internet. I am being facetious here, of course, but it illustrates how hard it is to compare our generation to previous ones. For example, I was never at risk for Polio, whereas my parent's generation was. Saying things are "better" or "worse" in a chart based on income alone is specious.
One interesting footnote on this graph is that it illustrates how difficult it is for the children of the very rich to exceed their parents income. This is probably due to two reasons. First, as I have discussed before, the children of the very rich tend not to be very ambitious. If you are set to inherit a million dollars the day you were born, there is little to be gained by risking that in business ventures or by working. Second, if your parent's income is very high then the bar for exceeding that income is that much higher.
One final note - statistics are fine and all, but negate free choice. I exceeded my Father's income level (by my best estimate - he never showed me his pay stubs!) because I chose to stop smoking pot and got an Engineering degree and a Law degree. My siblings made less than my parents (or at least had a lesser lifestyle) because they made different choices in drug use and college majors.
The New York Times loves a good victim story. And the narrative of so many of their stories is that it doesn't matter what you do in life as the deck is stacked against you. So you might as well not bother trying at all until the government steps in and straightens things out by paying off your student loans or providing a guaranteed minimum income or whatever socialist dream du jour is being touted. This is, of course, learned helplessness which can cripple an individual.
The New York Times is selling a lot of claptrap that is far past its "sell-by" date. We are in a new era, and it is clear that a large portion of this country isn't interested in Socialist solutions to our nation's problems, if indeed we even have major problems compared to the rest of the world. Left-wing thinking is what lost the election for Hillary - not income inequality.