The marketplace will decide if it's in an airport's self interest to modify for the A380. My guess is that the 380s going to be a light-seller and any airport that spends huge amounts of money to modify itself, is going to be sorry.
Maybe the Europeans shouldn't modify their airports for the B787. Opps, I forgot, that airplane doesn't need airport mods.
If the 380 turns into a hot seller then I guess the American marketplace will take a hit for a short period of time as mod are done. Right now, there's a lot more risk in doing expensive mods now, vice waiting for a while.
Sort of the same reason the Europeans want open skies. They want access into the large US marketplace.
When the Europeans gripe and complain about not American's not mod'ing airport to suit their very specialized and low rate selling airplane, that tells me that they have a lot more to gain than we do with the 380.