Hmm. In part. A huge chunk of this country is so rural, lots of rich farm land, it's open and spread out. The more rural areas tend to have less income. So for some of us there was a family history of poverty and/or very big incentive to be self sufficient.
I don't like the homesteading fad. Or maybe it's just the term that I don't like. This "living off the land" stuff is in my roots. Throw me into a big city like NYC and I feel claustrophobic, trapped, irritated at the crowds the noise the stink the concrete everywhere and unnatural manicured parks. I can appreciate it for what it is but don't ever plan on keeping me there. My ancestors were farmers or worked the land in various ways, fearless, independent, common sense smart, accents so thick no hollywood actor could ever replicate, lived hard and worked hard for every little thing they had. What I saw growing up was my family continued to grow their own gardens and raise chickens or cows etc as well as having a regular job or two, when times were tough you relied a bit more on the land and the fruits of your labor to see you through.
I don't know if this is the right answer at all but I think maybe "homesteading" is so popular because that particular way of life is still common and land available. So when you want to or need to and there's opportunity and means, I'm not surprised people do it.
Sorry for the book. Hope that makes sense.