I think it was a combination of cost, incompatibility (it typically required airports to fix their runways to accommodate it), and the above-mentioned fact that

I think it was a combination of cost, incompatibility (it typically required airports to fix their runways to accommodate it), and the above-mentioned fact that Airbus' core European market had largely moved towards low-cost PtP. The A380 makes sense only for hub-and-spoke, and/or flights over 4-5h. COVID was the nail in the coffin.