Personally I don't think that the 747 and the A380 really go for the same market. In the current market economy, airlines are struggling to get planes out full at the best of times, so it isnt all of a sudden going to be every 380 goes out full. If you look at the 737-900, then the 757, then the 767-200, 767-300, 767-400, then the 777, there isnt a huge step up between each of these planes, therefore there must be a market demand for each plane along the way. Airbus is the same, there isnt much of a step up between all their planes either. I have no doubt at all that there will be routes, and times of the year that the airlines can fill the 380, but it isnt going to be all the time, therefore the 747-400 will still be a very needed plane. Also I wouldnt hold your breath for a lot more leg room on the 380, at the end of the day, they will be cramming people into them like sardines, and whether or not you get an extra inch of leg room or something, you will still feel crammed when there are 555 other people around you. I have flown plenty of airbus, and plenty of boeing and as far as leg room, it isnt really the plane manufacturer that makes that decision, it is the airlines, and their reason for wanting the 380 is so that they can get as many people in that metal tube as possible. Airbus will say that it will be more legroom as being crammed with that many other people is the biggest objection to the plane, so they almost have to say that, but in the end, it will be more or less identical seat spacing to anyone else. Boeing would do the same. This isnt an A vs B opinion, I like both planes, I look forward to the A380, I think it is a needed plane and also a beautiful work of art.
The secret is to remain open minded about all of them. When the SC comes out, it will have teething problems and every airbus fan on airliners.net will be going on and on about it, and they will sort them out. When the A380 comes out it will have teething problems and all the Boeing people will have celebratory parties, but they always sort them out in the end.