Folks, the Skytanic has a role, and I'm sure it's a totally sweet ride. But it has two basic selling points:
A. fuel economy
B. pax/landing slot.
As far as I can see, the unique size and requirements of the A380 make reduced crew and maintenance costs an open question -- we'll find out more as it progresses.
Meanwhile, the on-paper claims of A380 fuel economy are on a par with those of Boeing's twins (A380 claims 2.9 l per pax per 100 km, assuming 555 pax and no luggage; 777-300ER also claims 2.9l per pax per 100km, fully loaded).
Pax/landing slot matters for a small number of airports, and these are usually the ones passengers (and crews) don't want to go to (LHR-JFK, anyone?).
But since most of the weight on a long-haul jet is equipment and fuel, the efficiency only comes into play at high load factors. So if you can stick a fully loaded 777 on a route instead of a half-loaded A380, you just made a ton of savings: in other words, that's fuel economy.
It's not a pro-American thing. Quite the contrary. There's always a strong desire to have the biggest, most powerful toy out there (well, at least for males). But is there a business case to match up to that? So far, the dozen-odd A380s flying around haven't demonstrated it.