I have read the dozens of A vs. B discussions on the A380. But one area that does not seem to get appropriately articulated is the economic risk of operating such a large aircraft.
We all know the costs of modifying airport infrastructure, etc. and the operational challenges... But from an airline perspective, we have witnessed several events during the past decade that would make the fixed capital overhead of these airplanes untollerable. Examples include: 9/11, SARS, Hong Kong Bird Flu... etc.
Clearly, this airplane will work under normal economic situations on routes where 1 plane is better than 2 (i.e. slot controlled airports and where lower economic per seat costs are compelling)... but during a major economic, terrorism, or health crisis, these will become absolutely cost prohibitive planes to run during that time to virtually any airport. Since there will relatively few airports that can take these planes, the ability to "shift" the flights to other destinations becomes challenging at best.
Whereas with the 777 or 787 sized airplane, the airlines will have greater flexibilty to operate the plane to different airports or even shift them to domestic services, etc. The other challenge lies in the winter vs. summer USA to Europe schedule.. and to a lesser degree the USA to Asia routes. We all know there is way too much capacity in winter. Flying A380s throughout the winter will be challenging from a yield perspective.
By operating two flights with smaller aircraft, the airlines have the ability to operate two at peak seasons, and shift the capacity to other "warmer markets" in the winter season. This lack of flexibility with the A380, I believe, will translate into operational risk on a scale significantly greater than the 747. There is a great economic case to be made for capacity "granularity"... which the A380 is not well suited for.
The additional per seat mile operating cost advantage of the A380 can be quickly destroyed with another global "situation"... and by flying the aircraft during off-peak seasons.
I truly believe that it is these "harder to quantify" risk elements of the A380 that rarely get discussed .... that will lead into the economic demise of the airplane.
I believe that when the 747 came onto the market, it truly broke ground not only for its capacity... but for its RANGE! The airlines were willing to take the risk of such a large aircraft because it was the key answer for offering non-stop flights to more markets from the US to Asia / Europe to Asia / Australia etc.
Today, as the A380 comes on line... while its range may up the ante a bit... there are many alternatives for airlines to get the "range" that they need for non-stop services. Hence, airlines main driver to take on the risk of the A380 is solely for capacity purposes. This lack of flexiblity coming from a such a captial intensive plane may hang airlines from a cost perspective under unpredictable global circumstances.