I think you're missing the purpose of the A380 WhoopWhoopWhoops. Rasobey's post is spot on. Whatever the configurations and subsequent fuel burn per pax figures, on high density routes where 400+ pax travel each day, it's far more environmentally friendly to fly 1 A380 than two 777s. That's why so many airlines have ordered it because it's cheaper.
Now if the A380 is only half full (or half empty for those that think differently to me
) then you have a valid point.