OK, after reading your article and your study, here are my thoughts:
1. You're relating a "problem" that is experienced by the upper echelon of earners in this country to the population as a whole. Those that experience these "treadmill issues", if you will, are those that have the ability to take advantage of technological advances, that have jobs where working harder and for longer hours will actually get them somewhere. I hate to say it, but in a lot of blue-collar (read: middle class) jobs, that's just simply not the case as much as in white-collar occupations.
2. The study raises a good point in that a person's perception of what will make them happy could be mis-aligned if they're only going after greater income and advancement.
3. This does not apply to the unemployed... which is significant, because part of the reason the economy is stagnant is because unemployment is relatively high, and it's hard to get a nation to fire on all cylinders when some of those cylinders are not being fed any fuel.
4. This also does not apply to those in lower income ranks.
Regardless, I stand by my initial point - you're talking about a social phenomena. Both of those items you had me read were coming from the perspective of happiness...but only the Times article takes into account productivity, and even then its results are fairly inconclusive, and have more to do with corporate culture than with an over-arching social phenomena. Again - you're dealing with a limited pool of subjects to study.
Would shiny, happy people working in their jobs being optimally productive help the economy? Sure, it would. But that assumes everyone's working (which they're not) and working in positions where they're able to be optimal (which won't be the case as long as we've got significant undermployment in some sectors, like right now).
I just feel like you're really stretching here, trying to tie unhappiness as a primary reason for our sputtering economy. We've got to get the engine running first before we can fine tune it.