1. Landing slot price per passenger is low. Congested airports are the economic reason for A380 to exist.
2. A380 is runway-friendly large aircraft due to its wheel load distribution and low load per wheel. Airfield pavement maintenance cost is 30-40 percent of the airfield maintenance. If the weight based pricing is changed to match actual runway damage, A380 will do really well.
3. Relative to 747-400, significantly better fuel efficiency.
Economically A380 starts to make sense again in 10-20 years after the traffic volumes in Asia skyrocket. When the demand exceeds the slots available, the value of existing A380s starts to increase.