Yeah, agreed, I've had so many conversations about this where people like the idea in concept but when you hear about people actually living in these it quickly becomes clear that it doesn't work for some folks. Specifically, though, in the 400 SF version that we'd like to build next (assuming we're able to actually sell the smaller one we're currently building) it would be on a 30-foot trailer and actually have two sleeping lofts. In that model, a minimalist family of 4 (minimalist, he says, as if!) could totally fit with the two adults in one loft and the two kids in another. At 3 children you start getting more difficult, but I'm sure you could do a 600 SF house, but then a trailer large enough to build such a thing becomes difficult to move.
Re needing a truck, plenty of folks tow tiny houses so that's no problem assuming you don't want to constantly move it. If you wanted to be truly mobile I personally question whether a tiny house really is the right vehicle (ha!) for that lifestyle. And the trailer we're using has jacks, which stabilize the trailer so, no, it's not semi-permanent, but when you jump around in ours you can't feel it moving at all. We also had a thought about adding a skirt to the trailer itself to increase curb appeal if someone purchasing it is going to leave it fixed in one location, but that's for when/if we sell. Gotta finish the interior first.
Re needing a truck, plenty of folks tow tiny houses so that's no problem assuming you don't want to constantly move it. If you wanted to be truly mobile I personally question whether a tiny house really is the right vehicle (ha!) for that lifestyle. And the trailer we're using has jacks, which stabilize the trailer so, no, it's not semi-permanent, but when you jump around in ours you can't feel it moving at all. We also had a thought about adding a skirt to the trailer itself to increase curb appeal if someone purchasing it is going to leave it fixed in one location, but that's for when/if we sell. Gotta finish the interior first.