I get the impression that Canonical is more focused on user interfaces than on drivers and plumbing, so maybe they were not the best choice for this kind of work.
But I absolutely don't buy the idea that Debian or Red Hat is not a reasonable starting point for an embedded distribution. I guess part of the reason I feel that way is because in the past, I've worked at two different companies that have done exactly that. One company used Red Hat 9 as the starting point for their embedded distro; the other used Debian.
It would be nice to see touch-screen support and bluetooth-as-a-device support in mainline Linux, but that hardly justifies a completely new distribution. I guess getting X to work with touch screens was always going to be fugly, but Tizen uses X anyway, so they have to solve that problem anyway.