Would you? Really? Cause I have been using Linux exclusively for my servers, desktops and notebooks for years and I didn't know there was a "laptop" ubuntu. Or suse. Or redhat.
Actually, I still don't know that. But I will take your word for it that something like that exists in some niche under a rock. Everything does. Linux distros are like porn on the net, if you can think of it, someone has done it. And heck, there are probably even supported ones from the three distros above maybe. Just I never heard of them because I haven't cared enough to look.
Which brings us to the odds of "the average computer user" having heard of them: Zero. Zip. None, Nil.
Plus, they have absolutely no conditioning for it, coming from either Mac or Win, where you don't need a magic special install to make your laptop work with your OS. You just do it.
So basically this isn't negating the OP's point, but instead reinforcing it. It is just another reason for people who aren't geeks to say: linux, I tried that but my battery life cut in half, so I put Win back on my machine.