All they need to catch up is some fit-and-finish and that little pinch/unpinch trick for zooming.
Yes, well... Horseshoes, hand grenades and thermonuclear devices and all that. Seriously, the only thing that really sets one operating system apart from another IS fit and finish. Something the Linux On The Desktop (or laptop for that matter) have never really figured out. Aping pieces of Windows and OS X (I notice modern distros seem to have BOTH a start bar AND a global menu bar... why?) will never get you fit and finish. Some poor bastard (bastards most likely) sitting down and smoothing the hell out of the rough interface edges is what's going to get you there.