Bigger is Better
Bigger is Better, that was the thought promoted by the leaders of PanAm and Boeing in the 1960s and along came the 747. It is a very complex story. Bigger is Better is the name of Chapter 6 in the book The Sporty Game written by John Newhouse. This book gives great insight into the complex world of airlines, aircraft and of course, the jet engines that power the aircraft. It is a fascinating read.
The 747 was successful as it was because it had no competition and if didn't work as a passenger aircraft, it was designed to be easily converted into a freighter and many have been.
The A-380 doesn't have the luxury the 747 had and today's market is different. Technology developments and enhancements for both airframes and engines have come along more rapidly than ever before. The A-380 and 747-8 programs are not long runway programs and neither manufacturer will make money while covering development cost no matter what the bean counters report.
The money making long runway programs are the 737, 777 (including new advancements) A-320 and A330 (including new advancements). These are the aircraft that will serve the most customers, generate the most profits for the aircraft manufacturers and the engine manufacturers that have engines on them. The revenue stream will be long lasting with service and replacement parts. IMHO, it remains to be seen if the 787 or A-350 programs will be long runway profitable programs or not.