The purchasing power of the average American has gone through the roof in the past 30 years.
Just look around your house at all the stuff you own and compare it to what you had growing up.
The life style we live today is 100% better than what we were living with 30 years ago. Even the poor have multiple tvs and air conditioning etc etc.
This is true, though it is increasingly financed with debt. Younger people often don't understand how much material wealth has increased. In part I think this is because there is so much more to buy today, and it lasts less long. When I was a kid we had very little, but you didn't miss it because the things other, richer kids had weren't that different. Tennis shoes from KMart were not materially different from those from specialty stores, baseball mitts without a famous player's endorsements weren't materially different, even color televisions weren't that big a deal because kids never got to choose the channel anyway.
Where we're really screwed today is not in average salaries, but rather in our loss of wealth-producing jobs and its ugly step sister, debt. Government has taken money and spent it, assuming that future revenue would always be greater. To a great extent, large mega corporations did the same with pensions and promises (lifetime health insurance.) We're still on an ever-upward spiral of increasing material wealth, but we no longer have the means to buy it except through debt.
Even worse, those of us who are not buying things we don't need with money we don't have to impress people we don't like are increasingly being forced to pay for those people who are. Hell, if I HAVE to pay for a McMansion then I want it to be MY McMansion!