The fundamental problem for the A380 is that it will always be more of a financial risk unless an airline can guarantee to fill it consistently (year round) at reasonable yields. There are some routes where filling them is possible, for sure, which is where the A380 reigns. But on any given trip, an A380 will burn more fuel (and thus cost more to operate) than a 777 / A350 / 787. With seat mile (cost per passenger per mile) not that far apart, that's fine if the A380 is consistently full. But in a lot of cases it's easier to sell 300-350 seats than it is 500. Increasingly with sophisticated revenue management operating in the background airlines will chose take fewer passengers at good revenue and turn away the cheapest business, rather than discount heavily to fill another 150-200 seats or fly thin air around.
So it boils down to:
* Can I make a profit flying an A380 - probably yes if I can fill it at reasonable yields
* Can I make a profit flying a 777 / 787 / A350 - probably yes if I can fill it, which is less of a challenge
* Can I make more profit flying a full 777 / 787 / A350 than a I can flying 2/3rd full A380 - quite pobably
* Can I make more profit if I have to deeply discount to fill the extra seats on an A380 - possibly not
Therefore in many cases bean counters see the 777 / 787 / A350 as lower risk, and potentially more profitable. Even as airport constraints get more severe some airlines will chose to keep a lid on capacity and leave behind the really cheap business they would sometimes need to fill an A380.