Image: Lazy office worker © Frank Gaglione, The Image Bank, Getty Images

American workers have hit a wall.

For years, productivity has been the U.S. economy's saving grace. I'm sure you're heard this line: Sure, American workers cost more, but they're the most productive in the world.

That's changing. For the first time since the recession ended, businesses are increasingly unable to squeeze more and more work out of existing workers. Workweeks have been maxed out. Manufacturers are increasingly turning to expensive overtime to fill orders.

Yes, with corporate profits at record highs and millions still out of work, it's hard to feel bad for those in corner offices poring over résumés. But their job has gotten tougher. Rather than hiring from an eager, skilled and educated reserve army of workers, recent data suggest they're facing an emerging skills shortage.

Labor productivity, a measure of how much work is done per hour, has plunged over the past four months while labor costs have spiked toward pre-recession highs. The unemployment rate has dropped dramatically. And yet wage growth has stalled.

Translation: Companies appear to be hiring more less-skilled and less-motivated workers at low pay levels to get the same amount of work done. That's crimping profit margins and pushing inflation higher. At the same time, many qualified workers seem to be turning up their noses at jobs they see as demeaning, or that don't pay what they need, and they are deciding instead to leave the workforce, trying to strike out on their own or retire.

Image: Anthony Mirhaydari

Anthony Mirhaydari

You could read these data to suggest Americans are getting lazier, losing their skills or letting them fall out of date, and choosing not to take jobs they view as beneath them. Or you could fault employers for not offering enough rewards to interest even the long-term unemployed.

Both are true, to some extent. And to me, a deep dive into the jobs picture suggests that what we're seeing is an across-the-board erosion of Americans' can-do spirit. It's a change that will have wide-ranging consequences on everything from corporate profits and Federal Reserve policy to the overall shape of the nation's economy for years to come.

Let's take a look at two key age groups that illustrate the problem. Then we'll zero in on how it impacts the economy and investing.

The young and the feckless

This laziness dynamic, to the extent it is present, seems to affect the young rather than the old, men more than women, and the uneducated more than the educated. The overall drop in the men's labor participation rate -- the number of American men who have jobs or are actively looking for one -- is shown in the chart below. It's fallen to near 70%.

Labor force participation rate -- men

Part of this is no doubt due to the overall economic picture; job creation hasn't been high enough to keep pace with population growth for years. America is also aging, but this isn't just older people stepping out. The numbers are particularly painful in the 16- to 24-year-old male demographic, with workforce participation falling from nearly 80% in the late 1970s to around 58% now.

Is something else at work here?

Charles Murray, a frequent and controversial commentator on racial issues, has gotten a lot of attention lately for his recent book, "Coming Apart: The State of White America, 1960-2010." He paints the problem as a cultural one. Society seems to believe it's better to be a young idealist who's above lawn-and-garden work or a part-time college student who's more focused on music and Ultimate Fighting Championship fights than to be a 9-to-5 go-getter.

He also theorizes that, with female-dominated sectors such as education and health care being relatively healthy parts of the economy, men are needed less and feel less pressure to work. In a recent piece in the Wall Street Journal, Murray writes:

"Whether because of support from the state or earned income, women became much better able to support a child without a husband over the period of 1960 to 2010. As women needed men less, the social status that working-class men enjoyed if they supported families began to disappear. The sexual revolution exacerbated the situation, making it easy for men to get sex without bothering to get married. In such circumstances, it is not surprising that male fecklessness bloomed, especially in the working class."

Murray suggests these feckless young adults should be the subject of public scorn. After all, Americans used to share a moral imperative to be productive contributors to society, not couch-surfers wielding armories of Apple products. Similarly, David Brooks of The New York Times, also concerned about the rise of young, listless males, suggests one fix could be subsidies from the government to encourage men to, at the very least, get married and be responsible parents to their children. (I wonder how that would fare in Congress.)

Truth is, this explanation sounds a little too easy; these aren't the first old guys to complain about "kids these days." Getting a job that will pay the bills is tough; it can seem that work doesn't pay. And fecklessness isn't the exclusive property of the young, unemployed and poor, as any number of nauseating "Real Housewives" spinoffs prove regularly on reality TV.

But their "feckless young" are my peers, and I can tell you they have a point. Clearly, there is work to be done, both literally and figuratively.