They are. Though I’d be a little claustrophobic in an 8 wide.
The desirable, structurally sound ones were designed to be road-worthy, like the Spartan. So, the widest you’ll see is just slightly over 8 feet. If it’s just you or you and spouse, it’s not that bad so long as you stay on top of the “stuff” accumulating over the years. It takes some effort to keep it in check, annually editing it down to fit.