I just don't understand that argument, on two fronts: First, Elementary looks almost exactly like a stock Fedora Gnome desktop (slightly clunkier, actually, in terms of window decorations and the settings panels)...so, how is it uniquely pretty in the Linux world? Second, I consider recent Gnome on Fedora to be comparable to Windows and mac OS (preferable, even, IMHO).

Linux from several vendors has been pretty for years. Being pretty, or historic lack thereof, clearly isn't the thing keeping Windows and mac OS users from switching in droves.