Airlines and manufacturers pushed very hard to make the A380 work, and it was just a prestige project in the end that failed badly. It might work, it might not - I'm suspecting it's a risky proposition and hope it doesn't end up being another prestige project.
I'm not sure that that's an accurate categorization of what happened with the A380 though.
As we all know, it was designed to move mass amount of pax from A to C, but via B. Its fate was however sealed when (1) new technology opened alternatives to what it could provide (e.g. moving from A to C with no need for B), and
(2) they did so at equivalent or lower cost, while (3) allowing airlines to charge a premium for the nonstop to a smaller market with fewer competitors.
The A380 (and the laughably impotent 748i) could not survive that tripartite assault.
The same cannot be said for ULH though. Until we invent a teleporter, nothing's going to get the mass amounts of people (that QF reasonably believes exists) from Oz to Europe faster than a nonstop.
And if these new generation airframes and/or engines prove their mettle, then it's quite possible that nothing's going to do so as efficiently either; rendering it just another evolution in the longhaul market, similar to the past.
I myself, suspect a more prosaic motive... ~Thranduil