Is 40 middle aged or just the beginning?

Lately I seem to know a lot of people in their 40's who seem tired. Not physically tired, but just mentally done. And with the prospect of a couple more decades of work ahead of us (and maybe then some), it seems that people no longer look at their current professions as something they're going to be doing the rest of their lives. Last year my husband went back to school, and went from sales to being a massage therapist. I know art directors who have no desire to return to their job after having kids. The days of the gold watch seem to be over, and as the economy gets worse (did we need the government to tell us we're in a recession?) it seems that more people are not only looking for new ways to earn a living, but looking for ways that are a 180 from what they studied in collage. I know in my own industry, it seems that there's been a shift from understanding design to being able to program. Are we seeing a shift into going from a generation of consumerism to one that is looking for what will keep us happy? Maybe only from the tough times can we really appreciate what we have. Maybe it will no longer be about the car you drive, but about how much time you spend doing something that makes you happy. Because no one ever looked back on their lives and wished they worked more.