I'm guessing there are a ton more people in the younger decades of life than in the older ones who still cherish the greatest music of all time.
(Emphasis mine)
That is where this argument fails. 60's and 70's music is great to those who lived the era when those songs were "currents". It is far less relevant to someone born in the 70's who grew up on 80's and 90's songs. Or someone born in the 90's who grew up on 00's and 10's songs.
Each generation has their music. And many, born further in the past, also accept and enjoy the music of subsequent decades and eras. But, to most of us, the music of prior generations is not appealing (unless you look at timeless music like classical and some jazz); it was "our parent's music".
I grew up on Buddy Holly and the Four Seasons. There are some songs from that era I still like to hear... but most are tiring and, just, old. I loved a lot of the 70's, including the Bee Gees and even Manilow. I don't want to hear "Born to be Alive" or "YMCA" any more. 80's the same... lots of great songs from Michael, Police, Madonna, Dire Straits, REO Speedwagon. Some are still very listenable.
Even the 90's with Red Hot Chili Peppers, Dr Dre, U2 and even some of the Euro Dance like Castles in the Sky. I can re-listen occasionally. I can say the same for the last 20 years, too, although most of my taste changed to country, reggaetón and vallenato in that period.
But my point is that each decade and every year seems to have plenty of songs that are just as good as a year ago and a decade ago and two decades ago and...
It's a lot more fun not to be stuck in an era. That means ever time I hear the radio playing a current based station (or ask Alexa to spin some songs), I can be surprised with something new to add to my repertoire.