This COULD be a bad thing. A good economy is one that maximizes productivity while helping workers find a work-life balance. If this trend continues, soon we are going to see an increase in the number of people with illnesses related to stress/fatigue etc. Besides, it could also be due to the fact that american workers have lesser bargaining power than workers in other nations.
Again, I am not saying all of this is all good or bad. There are obvious benefits with our capitalist economy as well. Just that we need a good balance between approaches and currently, we are little outside of average, that's all. Whether that average is the right balance point, no one knows.