My creds, I saw the original broadcast of that first Beatles' performance on Ed Sullivan; I was 17 at the time (and really envious of all the attention they got from those girls.)
Now to try to make an objective comment, or at least to try to figure out the phenonemon from an objective rather than a 'get off my lawn'/'children no longer respect their parents' perspective.
The technologies of recording and broadcasting must have profoundly affected our relationship to music. I say 'must have' because I've never lived in an environment that wasn't saturated with opportunities to hear music. In fact, music is thrust upon me, and I have to tune it out. I do think the money people cheapen music, just like they will cheapen food, or clothing, or whatever. I'm nostalgic for the old fashioned disc jockey experience, and college radio stations where the student DJs would find stuff they personally liked with various idiosyncracies.
I read somewhere about an Irish fiddler who may have been the first to record Irish fiddle music. His record was a big success, so after that, all the other Irish fiddlers started copying his style, abandoning their own unique styles, which are pretty much lost now. (Sorry, I don't remember details like the name of the fiddler, or when the record was made, though I think it was the early 1920s, but there's a lesson in there somewhere.)
Fresh new music has I think usually come from places that were a bit isolated, but which could then be introduced to the rest of us through the new 20th century technologies. Jazz exploded on the scene with the Original Dixieland Jazz Band, not because they 'invented' jazz or were the best of their day, but because they were the first to be recorded.
Early rock and roll or thythm and blues was not encouraged by the industry, but the young picked up on it. And I think nowadays, the industry is always catering to the young, because they are the ones who will spend money on this stuff. Each new generation of musicians grows old with their own fan base, except that yes, nowadays, there don't seem to be any new generations of musicians that capture a loyal base the way Elvis Presley, the Beatles, or Led Zep did. (BTW, I'm 'too old' to appreciate Led Zep myself.)
I'm not sure why that is (That no Elvises or Led Zeps show up anymore), except maybe there is no place for a new sound to grow and mature away from heavy marketing influence. I have a CD of 'ska' music from Jamaica. It's old, primitive stuff, but the musicians there had a chance to hone their sound until it became polished, solid reggae. I think that's because Jamaica at the time was isolated enough, without being too isolated, that they could do that. But where is a place like that now? Instead the music industry marketeers are ready to grab and squeeze everything as soon as it shows as a blip on the radar.
When I search out new music to my liking it's usually older music in genres I didn't pay much attention to before, older Country, old Jazz and blues, partly that's because the lower quality stuff has been filtered out for me already. If I try to listen to new stuff, I have to wade through a lot of mediocre and downright awful along with everyone else.