Like other have said, if I am going to book a 20+ hour flight, I will specifically pick the flights that are A380 over either 777 or 747, and I simply would not consider anything narrow-bodied, if this means paying a bit more, so be it.
But would you turn a 10 hour flight into a 16 hour flight with connections just to fly an A380? Because for most people that's the choice they are making. They can take one airplane to a superhub (likely a narrow body), connect to an A380 (that may not even be going to their final destination, so there could be another connection involved). Or, they can take a big twin non-stop, bypassing the superhub.
In my case, I fly Seattle/Incheon on occasion - I can make a 3 hour flight to LAX on a narrow body and get on an A380 (that will then fly within 150 miles of Seattle on the way to Korea), or I can fly a 777 non-stop Seattle - Incheon and get there in a fraction of the time. I did the LAX stop last year
just so I could fly an A380 (and yes, it was quite nice - I was in business class and I loved the vodka bar in the back). But I doubt I'd do it again.
Seattle is turning into a major hub to the Pacific (it's significantly closer to most of the Pacific Rim/Asian destinations than LA or San Francisco). 20 years ago it was mainly 747s. Today it's nearly all big twins - 777, A330, 767, 787, and the occasional 747. No A380's serve SEA, and that's unlikely to change.