You're all assuming the A380 would fly full loads all the time, which agreed, it would make more money than the 777 on a per flight basis.
...however, the 380 costs a lot more to purchase. Do your figures include higher lease/"mortgage" payments? Higher overflight and landing charges?
What do you do with an A380 between longhauls? Send it on a MNL turn? How about the additional costs of buying and running sims, paying to keep more manuals, maybe another fleet office, crew and engineer training etc?