The Very Large Aicraft’s failures

In the late 1960s, the Boeing 747 revolutionised aviation, introducing the concept of the widebody aircraft and attempted, already back then, to alleviate the growing problem of airport congestion. Some 40 years later, the Airbus A380 was designed and built for the same purpose, only bigger.

Whilst the 747 was extremely popular at the end of the twentieth century, neither its newest variant nor the A380, commonly referred to as the Very Large Aircraft (VLA) category, managed to break through in significant numbers in the new millennium. What caused this lack of popularity?