When it is suggested that you could re-engine an A380, what would you replace the RR Trent 900s with that would be significantly more efficient, and what would that cost per airframe? One of the factors that isn’t going to go away is the Dry Operating Weight of 280-300T, equivalent to ~2 777s or A350s.
I like the A380 as a passenger but compared to the competition, both internal and external, it’s heavy and inefficient. That’s not so important if you can cram it full of premium passengers on routes that aren’t that fought over but you’re not going to be able to win on price against twins...