Why is U2 The Greatest Band Ever

Despite being routinely described as one of the world’s most popular bands on
and off for close to twenty years, U2’s reception is difficult to assess. Many sources
indulge in hyperbolic discussions regarding the “greatest” bands in the world, but what
exactly constitutes “greatness” in music, and, in particular, popular music? Album sales?
Longevity? Membership in the Rock and Roll Hall of Fame? Critical reception?
Influence? Originality? How would you define greatness ?