Spitfire,
It's all about utilization/volume when you participate in a "commodity" and low-margin business.
EasyJet makes money because they operate like Southwest and turn around their aircraft multiple times a day - that is the only way they can make money with such low fares - by reducing "unit costs" and keeping the aircraft moving...
Making serious money on long-haul would require either a lot of uncomfortable seats, a super low-cost operating structure, and probably "medium-haul" routes of less than 7-8 hours. If you could get two or three full flights in the air on a daily basis (using a full 747), then you might be able to make some money if the cost structure is low enough...
I suppose the capital costs on 747 Classics are reasonable now so that you could purchase a bunch for the cost of a new 747-400... Of course, maintenance could then become an issue with older aircraft...
If Easy were to start-up an operation like this, it should use a slightly different brand name - maybe "Easyhaul"... I doubt loyal Easy passengers would mind the "no frills" concept since they are already used to it on the short-haul flights...
. .Cheers