Take it up with these guys:
In the last study, the A380 had lower seat mile cost than 777-300ER but was beaten by the 777-9.
https://leehamnews.com/2017/01/23/22074/
Seat per mile cost doesn’t win in very scenario... This whale will win on SUPER LONG ROUTES between 2 airports that have the capacity to support the beast, but few airports have that ability, leaving this as a NICHE airplane, only viable between limited locations with HIGH DEMAND for the route...
In other words.... the things has been largely a dog.