I seem to recall once knowing what it meant. Something like having a good job, a family (usually with a few kids), and living comfortably. I could be remembering incorrectly and/or forgetting things, however.
As for whether I think it's still alive or believed in, maybe for some, but not in my circles.
How much do I care? I think it's very telling how much I personally care based on how well I remember it. Which isn't well at all.