Well they obviously need replacing at some point, whether by other 747s or other models... The current ones are already old flying rattle traps with substandard hard product not worth refreshing because of fleet decisions and the age of the airframes...
Well the product may well be beyond its use by date, but the 747 ERs should have some years left, and are far from being rattle traps. They were a very nice update of the original -400. Rumour at the time had it that QF tried to get some more, but Boeing pushed them towards 747-8 or 777, neither of which they wanted. One was pie in the sky at the time, and the other was something they'd already decided against.
In a more normal world, the likes of Geoff Dixon would never be permitted to buy aircraft. He dismissed the 777, which whilst not suitable in all variants, would have been an excellent fit in others. The A380 is an excellent example of why you should never buy the -100 model of anything, especially, as it's now going to be the only model (and yes I know what the real model number is).
With Project Sunrise, QF is definitely heading down the path of big twins - my bet is the 777, the only other option the A350.
It will be interesting to see how that pans out. My bet is the Sunrise will never eventuate as more than a niche offering. How many people want to pay a premium of 30% on their fare to save an hour or so.
My feeling is that the 350 is actually a better fit, but we'll see.
How long will they keep A380's? Who knows, but I doubt they will ever order more. They are just running the 747's until end of useful service life - there is no future room for similar aircraft.
Someone forgot to order appropriate replacements.....
They have 8 on order that they keep deferring and I expect will never be delivered.
Particularly with the rumours floating around today that EK will switch A380s for A350, which will likely mean the closure of the A380 line
As Airbus have actually sued one airline, and forced them to take delivery, this will be an interesting outcome in itself. These are orders, not options, and AJ will be praying for the 380 line to close. Even then I could see legal action, perhaps with a goal of forcing 350 purchases to offset those 380s.