Variety is the Heart of Linux (Score 1)

I do not forsee a single Linux UI becoming mainstream any time soon. Variety and open source projects are the very core of Linux. There will always be things one person favors over another and so on. Sure, maybe all distros will start shipping with the same default UI, but not everyone would adopt it, ever. Unless said UI contains options that would allow you to make it look like basically every currently popular UI (*box, enlightenment, etc). But then you'd have pages upon pages of configuration options.