in 2007 and 2008 i have got many people (of every kind) to use ubuntu as their only OS.
i do this not just because i like what upuntu stands for and promotes, but becacuse with ubuntu i do not have to repair my friends computers nearly as much as with windows/osx.
the latest ubuntu is made for humans, its not what one would think of as "Linux" at all. linux used to be just for geeks, but ubuntu (partly because of google) has been updated to be easier than any other os.
people say mac is the easiest, but i say it is not. besides, ubuntu is free.
you are right in all that you say, but i feel like the world unfairly thinks of ubuntu as just another "linux" os. ubuntu is its own world, and its a beautiful one.
my ubuntu currently looks exactly like vista and runs many times as fast.