They turn out to be just too big.
Looking at maps it looks like they mostly see service on long distance routes, especially from London, Singapore, Dubai, Johannesburg and Sydney.
Other than that, I guess airlines just found them too big, and prefer more frequent flights of smaller planes.
I have never flown on one, and have no idea if they are comfortable or not. The cabin looks so crowded though.
In February 2019, Airbus announced it will end the A380 production by 2021, after its main customer, Emirates, agreed to drop an order for 39 of the aircraft, replacing it with 40 A330-900's and 30 A350-900's. Airbus will build 17 more A380s before closing the production line – 14 for Emirates and three for All Nippon Airways – taking the total number of expected deliveries of the aircraft type to 251.
Airbus would have needed more than $90 million from the price of each aircraft to cover the estimated ~$25 billion development cost of the programme. However, the $445 million price tag of each aircraft was not sufficient to even cover the production cost, so with Airbus losing money on each A380, and orders evaporating, it makes economic sense to shut down production.
Enders stated on Feb 14, 2019, "If you have a product that nobody wants anymore, or you can sell only below production cost, you have to stop it."
One reason why the A380 did not achieve commercial viability for Airbus has been attributed to its extremely large capacity being optimised for a hub-and-spoke system, which was projected by Airbus to be thriving when the programme was conceived. However, airlines underwent a fundamental transition to a point-to-point system which gets customers to their destination in one flight instead of two or three.
The massive scale of the A380 design was able to achieve a very low cost for passenger seat-distance, but efficiency here within the hub-and-spoke paradigm was not able to overcome the efficiency of fewer flights required in the point-to-point system.
https://en.wikipedia.org/wiki/Airbus_A380#End_of_production
