You mean casual long-term windows/mac user, I suspect.
A user who's been taught by the OS not to use the keyboard much won't use the keyboard much - if they have to click into a box to do it in general, that's going to encourage it.
Ubuntu is attempting to make things better, not just copy the other desktop OSen. Maybe it'll work, maybe it won't. But the fact it's not what you immediately expect currently doesn't guarantee it to fail.
Of course, I really want Ubuntu to get into the touch space for that reason as well, because that's where casual users seem to be going.
It's already fragmented enough, not to mention that most tablets/phones are locked down and will prevent people installing an alternative OS anyway.
The only way would be to produce their own hardware since they won't make any money licensing their OS.
If they're as good at hardware design as they are at software.. I think I'll pass.
there "were" plenty of casual ubuntu users. soon there will be plenty of casual mint users.