Dinger,
I think your economic reasoning is flawed.
As you say fuel prices are going up and if (and its a big if) fuel production peaks in the next 15 years then this is a plus for the A380, not a minus.
It becomes less economical to operate point to point services with smaller airplanes with higher seat/km costs then the A380.
You are right about the decrease in traffic due to higher energy costs, this shows that the large a/c with the lower seat/lm costs will win out,less frequency, full a/c means lower costs and the hub and spoke system is here to stay.