I agree with your premise.  However, I don't get your math. Looking at the chart, and doing a little interpolation from the 2007 column, it looks like you should have started with a mean monthly income of $3700 not $4434 which was the 2016 mean monthly income. After the inflation rate of 15.8%, the mean monthly income should be about $4233. So actually after inflation the mean is really $201 per month higher. Not great, but a bit better. I'm not an accountant so others can check my math. Call me Captain Pedantic if you will. However your point about inflation and gravity is completely valid.