The open market has stated, repeatedly, that the average consumer is primarily cost driven.
Which probably is the reason why the premium economy has become a big market success, it is simply cheaper than economy class...
The market has demonstrated that if given the choice, people are willing to pay a premium for a better product. If however the product offered is inconsistent and you never know what you really get for your money, then of course everybody opts for lowest cost.
Those airlines who explicitly offer the A380 as premium product have succeded to sell the more expensive tickets.
You would have a hard job flying on an Air France 747 to anywhere - they do not have any ! They retired the last one at least 2 years ago.
You´re right, they switched some of the flights to 787 now. The A340 will soon be history on that route as well.
Anyway, they switched back from A380 to two planes within less than 2 hours, just like they did before there was an A380 available.
Most operators are replacing their old 747s with big twins, not new A380s
Because they do not need the extra capacity. They once bought the 747 for range, not for seats. Now they can have the 747 range with smaller twins, which allows a more flexible and diversive network.
Many even replace their old 747 with 787, not with 77W, as they do not need the size.
The hub concept requires efficient and convenient airports, most major airports of major cities however are very old, and have grown without a real concept behind. If it takes longer to change terminals at a major airport than flying to smaller airport and take a train or car to your destination, many people will do just that. It is not just the airspace or the runways, it is the full aiport infrastructure which prevents the A380 from using its full potential. Only a handful of airports worldwide is truly "A380 ready".
If you operate from an airport with overloaded terminals, you do not make your A380 passengers happy. And if you operate from small efficient airports, you can not fill an A380.