they had to do major rework on their wing ribs as there were cracks on the aluminum alloy, and while taking planes out of service considered densifying seats in main cabin, but these hardly constituted real optimization efforts. airbus has been reluctant to optimize with newer engines and configurations since 2015. here's a snippet from the aviationweek link provided by sam.
"Optimizing the existing aircraft is also Airbus’s way to buy time in the broader discussion about whether or not it should launch the A380neo, using latest-technology engines. That move has been heavily promoted by Tim Clark, President of Emirates Airline, but it has not found significant backing elsewhere. Clark has made clear that the airline would buy at least another 100 aircraft if Airbus developed the new version, although the manufacturer has more recently tried to push the decision further to the right. Airbus Group CEO Tom Enders effectively ruled out a launch before the end of 2015 earlier this year, diminishing Clark’s hopes that he could still convince Airbus of going ahead."
moreover, airlines will continue to add direct long haul routes that do not need to carry 600+ passengers per flight.