Maybe a good academic conversation, but useless
This whole discussion maybe a nice academic conversation but really only produce conversation not productive information. In some of the examples with a full load of fuel, moves the all the numbers. JAL at one time had 747's flying relatively short legs, but with something around or over 500 seats. Then throw in the 380, (one of the ugliest airframes in the sky, MHO) with a couple of showers with hot running water.
A better conversation would center around the direct operating cost of the airframe. The 777, 787 and maybe the 350 are fuel savers, that's why the airlines want them. The 380 maybe dead in less than five years, just cost to many liters of jet fuel to move the beast.
Fuel cost per seat would be a much better conversation. Or, how about cost per hundred kilos?
As long as the aircraft is above a relative size the passenger is more interest in frequency, than number of seats it carries. An airline offering four departures a day in a 737/320 as opposed to one 330 departure.
The 737/320 carrier wins.
Just my couple of pennies.