Because if you don't tow anything on a daily bases, then there's no need for one.
No they don't actually. that's a myth, your only talking a 1-2 maybe even 3 mpg difference not much. they are meant to be run constantly.
Just curious, but why should it matter to you if I want to get one or not? If I like it, I'm gonna get it. Maybe I like the way they look, or the way they perform, or their nice interior, or maybe I just need it because of all the heavy shit I carry. Who are you to tell me I don't need one just because you feel I don't need one?