You did a fair job on the article but I think there's some things you leave out. OS X is derived from UNIX. Apple put an industry leading UI over what's a difficult system to use and nobody seems to notice. While Linux, which is also derived from UNIX, you correctly point out it's UI difficulties. However, whose to say that a company or group could not take Linux and adapt it for smart phones. This is the approach that Palm is taking, but since they are at it for a short period of time it leads one to believe that they've got a long way to go to catch Apple.
Microsoft is an interesting candidate to create a version of Vista for the smart phone (as if they needed another version of Vista) however how likely are they to follow the PC makers and have Mr. Softie dictate hardware requirements to them for their OS?
I doubt that Symbian has the juice to catch OS X/Unix when it comes to running a scaled down PC which is what Apple is selling. I'm sure that won't prevent companies from trying to spruce it up and sell it on upscale phones. The problem is that it's going to take too long to develop (something that they just don't have) because they're solving a simple problem to a much harder one. Apple already solved the complex problem and only had to scale down OX X for a handheld.
The OS Wars Are Back