On the one hand, US is doing great. US grew 3% annualized last year, on a base of 19T, the most in the world. That's very impressive considering how big the base is to even have such a big percentage. You can compare that to China, where they had to keep reporting a fake 7% growth despite their provinces confessing to a 20-30% fake revenue. In the last 40 years, America's middle class shrank 7%. However, the lower middle class shrank 7% as well, and the upper middle class grew 16%. (http://money.cnn.com/2016/06/21/news/economy/upper-middle-cl...) . Implying that alot of the lower middle and middle had moved up. Especially in certain cities like San Francisco or Santa Clara, where there is just an abundance of $130k+/year jobs (and contrary to popular belief, one can easily save $50-60k/year by renting a room in a house at $1000/month).

On the other hand, it seems like the lower class has barely budged, and has remained in place and their quality of life has suffered. They have been losing manufacturing jobs to China and other countries (20M at the height in 1970, 12M currently http://money.cnn.com/2017/04/07/news/economy/us-manufacturin...). However, now with an administration dedicated to bringing jobs back from overseas (with focus on manufacturing), and enacting tariffs on countries that competes by flooding the market and destroying local competition, the jobs for lower class should be growing starting this year. The current solar/washing machine tariff, and upcoming steel and aluminum tariffs against China should help.