The New Yorker's John Cassidy discusses long-term trends in earnings and income in an interesting blog post.
Cassidy is right that trends in the statistics on median earnings and income are alarming, but there are a few more nuanced parts of the story that seem to be missing from this short piece. But perhaps they're in his larger work.
Average earnings and income have been increasing rather steadily. That there's a difference between trends in the median and in the average speaks to rising earnings and income inequality. Clearly a reason not to be optimistic for those in the left tail if they're stuck there, but a little more nuanced than pessimism-for-all.
Second, if one looks at total compensation or unit labor costs, one also sees a different picture, and it's because of the rapid rise in benefits, namely subsidies for health insurance premia. Trends in the average are strongly upward, and I imagine the same would hold true for the median, which I don't think the BLS or Census publishes (these are establishment, not survey data). Rapidly rising health care costs are painful, and we pay more than do those in other countries for what we get out of it, but let's not forget that Americans also living longer on average than earlier generations. (And yes, there is an inequality story here too.)
Finally, let's not forget that the story for women has been starkly different, whether measured by mean or median earnings. Surely the increase in female earnings, while perhaps not always directly good for men in some hyper-selfish version of the world with no partnerships, is an optimistic rather than pessimistic trend.