I think the idea is that they were the best at what they did - or in many cases may not have been the best but won out over others for reasons of fashion or luck which are all but meaningless to us now. Either way their victory became a genuine foundation for what we now call music. Without the Beatles other forms of music literally wouldn’t have existed - and countless others would have been markedly different.
That said, they were the first band to have their kind of success (particularly in terms of fan-worship). Other bands who are clearly crap now encounter levels of adulation approaching the Beatles’. But I can’t just accept that they were the first boy band. They developed from their sixties incarnation into a startlingly mature ensemble with astonishing vision. I can only think of a few bands, like Queen, who have since rivalled their “take on whatever comes” talent.
The bottom line, of course, is that Lennon and McCartney were Galton and Simpson, Gilbert and Sullivan, Moore and Cook, Simon and Garfunkel. Just one of those uncanny combinations of writers who WORKED. Every such event is worth noting.
My point isn’t that they weren’t good–the OP was about CNN interrupting war coverage to announce the death of one of The Beatles, with the question being whether they were so good that the death of a member would in effect be the most important news item in the world. My argument is that they weren’t that good, they were that popular.
What a stale, boring musical wasteland we would live in if musicians all decided it would be better to ape their forefathers instead of changing music for the next generation. One of the reasons that music sounds so diverse today is because of bands like the Beatles, who showed the diversity of sound that could exist within ONE GROUP.