It would seem there is a big difference between "camping" and "living" in a trailer or motorhome. I'm still able to enjoy camping out of a small van roughly 1/40 the size of our home, although my wife a little less so lately. The next one must be much larger to minimize the "roughing-it" factor.
If we were looking to live in it, we'd look for a fairly large RV, but for camping we want to keep it small to make traveling much easier. Plus a small RV makes us appreciate the room of a house that much more.