The first 747 was designed to carry almost 400 people from the East Coast of the United States to Europe, basically a double-decker bus on a relatively short haul service. Later versions and even later widebodies stretched those demands to cover the West Coast of America deep in to Central Europe and on "very" long haul flights to Asia. Today there are "Ultra" long haul flights such as New York to Hong Kong and Singapore or Los Angeles to Dubai. Surprisingly few of them today are served by the venerable old bird who started it all in the first place.
Why? Kinda simple, really. The 747 can't make it. Technology and fuel capacity can only do so much and most feel the 747 has been taken literally as far as it can go, the new "Dash-8" series notwithstanding (and that is a model still yet to fly in commercial service so no one really knows). Most of these ultra routes are flown with smaller planes that still have very large fuel capacities, making 16 hours between California and the Middle East a stretch but a doable one.
Qantas, long distance travel master supreme, has recently introduced nonstop service from Sydney to Dallas/Ft. Worth, my hometown. The aircraft they use is a 747-ER for "Extended Range" which means it is stuffed with fuel in every possible location, sacrificing some cargo space but not passenger room. The easy part is that Sydney to Dallas is flown with the wind at its back so the plane gets a nice push most of the way to help bridge the distance. Heading back down south is another story with absolutely no margin for error. Dallas/Ft. Worth is typically a three hour flight to the West Coast from which it is typically a 14-hour flight to get to Australia, three extra hours tacked on to an already long service.
Airline planners typically hope for "blue sky" conditions that will allow a flight to operate as scheduled...most of the time. Trouble is when you advertise nonstop service customers expect and accept no excuses for pulling over to get gas. For a variety of reasons Qantas does not want to stop between Dallas and Australia. Any island along the way such as Hawaii or Fiji will most likely charge exorbitant rates for fuel not to mention fees for landing and using their facilities in to the bargain.
Within a week of inaugurating service a story went out that called Qantas on the carpet for leaving three stuffed baggage containers behind as a weight saving ploy to allow a nonstop flight. It took another 24 hours for the affected customers to be reunited with their belongings. One has to wonder if only the Brisbane customers were affected; I'd hate to think of the mess it would cause if any of those bags were going to other destinations. Will it happen again? Sure, at some point. Has it happened before?
Some time ago in a bid to compete with Qantas to Australia United Airlines offered nonstop service from Los Angeles to Melbourne, also with a 747. It didn't last long because the distance was simply too far for the model United operated. Stops were routinely made in Hawaii for fuel until they finally threw in the towel, red faced from the exertion and humiliation. Melbourne is now only available on United after a scheduled stop in Sydney.
United tried again in a different market, offering nonstops from New York to Hong Kong but learned the same lesson. "Nonstop" service making a "technical" stop in Anchorage damaged their reputation and doomed the service after maybe six months.
Are airlines biting off more than their engines can chew with these extreme routes? Does anybody really want to endure 17-20 hours on an airplane (especially in coach) for the sake of avoiding a connection? One friend of mine sent one of his employees to Sydney from Dallas on assignment recently. That guy deliberately chose a connection via Los Angeles just to avoid the new service altogether. He got to stretch his legs on the ground for a couple of hours and enjoy the new A380 on the way down in to the bargain. Not bad, I say.