See [1] for a good summary. Then pair it with [2]. The full picture is, as usual, more complex than a catchy title can summarize, but the trends are pretty clear. If you're in the top 20% of earners, things are improving. If you're not, things are generally stagnant or getting worse. So we're heading for something that's kind of plutocracy and kind of a class-based system of "haves" and "have nots".

[1] https://www.pewresearch.org/social-trends/2020/01/09/trends-...

[2] https://www.pnas.org/content/117/1/251