It was too heavy even before they had to add bolsters to the inside of the wings due cracking.
ALL Airbus 4 engined jets have never come close to their advertised fuel efficiency. The A380 was and is the same. It burns a lot of fuel for a small uplift in passenger capability. Unfortunately it’s ability to carry the passengers bags and any useful amount of cargo is extremely limited.
The biggest issue with the A380 IMHO is the pavement classification. It’s an extremely heavy aircraft on the ground leading to airports requiring to make long term, expensive infrastructure changes in order to handle it. Not an issue if you are a ‘hub’ but smaller airfields don’t want the expense.
This has a fall out effect that many people don’t realise. If you have a limited number of major international airfields that can take your Super Heavy jet then the amount of viable fuel/weather alternates is reduced even more. Hence the jet often has to take an uncommonly high percentage of contingency fuel as the only available diversion might well be a fair few hours away! This all adds to the aircrafts lack of commercial performance.
The final nail in the coffin has always been that dropping an A380 onto a high density premium route was meant to reduce the number of aircraft needed on the route, the fees, the engineering and the crews etc. Most passengers paying for the expensive seats that make up the majority of the profit for many airlines predominantly want flexibility not bulk. One 380 a day is far less preferable to a businessman as 2 x 777 a day for example. Flexibility is key.
The aircraft is nice inside and very quiet when underway but its fuel burn, lift capability, range and limited destination options make it obsolete already in a world of point to point ULR twins.
Good business decision to kill it.