Well, I guess this is a matter of perspective. I expect to work, physically and otherwise, until I die. If I can't do basic activities of daily living, I'll need help. Such is life.
DH already has some physical limitations- without going into extreme medical details, he has a bum leg, from his hip to his foot. He grew up on a working farm, and despite having been through a hip replacement as a teenager, is strong as bull and has always worked physically demanding jobs, up to and including his current career.
We are still pretty young- I just turned 31, and DH is ten months younger than me. We have the major pieces- in DH's case, a thriving career, in mine, a degree, a small mortgage that we should, barring some unforseen tragedy, have paid off within seven years, health insurance, retirement, and our kids' college expenses taken care of.
We already do what we can- we process the vast majority of the food we eat, rather than buying packaged, we've minimized the number of appliances, large and small, that we use, we were some of the early adopters of of CFLs and eagerly await the next generation of LED lightbulbs, we use a non-electric camera obscura type projector instead of buying a flat screen, we have made lots of energy improvements to this house, with insulation and greywater reclaimation next on the list...
Given our "assets", I think if anybody can do it, we can.
The big drawback to our current house is that it is not at all handicapped accessible. The one bathroom is up a twisting staircase, to give an idea. So if/when we build, we'll be building a good size house (1000-1200 sq ft footprint) with a walkout basement, and we plan on putting a handicapped accessible apartment in the basement. That way, if need be, we could "rent" the main house (it would be minimal rent) to our child(ren), even if they had a family, in exchange for property/animal caretaking responsibilities. If none of our children are interested, it may take more looking, but we could probably find some other trustworthy party.
(I actually stole this idea- DSS's grandma is the "caretaker" in a stituation like this. She lives in the same house as the elderly property owners, but in her own apartment, and pays the electric bill as her rent. The caretaking responsibilites amount to a part time job, in her case. She also works another part time job, and does all kinds of fun stuff like going to Jamaica and collecting handbags. I know for a fact that she is debt-free, so I presume she could live on quite a bit less than what she actually makes.)
I guess my point in all this is basically to back up what That Is Nice pointed out upthread- you could live $14K per year, in lots of places, IF you have the major pieces already taken care of. So when you input those other factors, is it really $14K? If you are standing on the shoulders of giants, do you praise yourself for being able to see farther than others? Even in the case that the giant's shoulders are a lifetime of work?
It's interesting to think about.