I don't know about past generations, but in the case of my generation, it's because new music has been horrible since about the late 90's.
As an example, I'm deeply into progressive rock. One could think that after the 70s the genre would be completely dead, which is not true. Of course listening to TV or FM radio could only reinforce that idea, but thanks to Napster back in the day, and a simple search years ago that brought a couple really nice online radios (0,1), I discovered a number of great modern artists and bands. I passed my mid 50s and I wish I could know 1/10 of the artists I discover each year today when I was in my 20s or 30s.
(0) http://www.themusicalbox.com.ar/tmbradio.htm (Argentina)
URL: https://tmbradio.radioca.st/stream
I submit that this is happening because the newest popular music simply isn't as good as it used to be. It should be as weird to hear a teenager listening to Zeppelin and the Stones today as it would have been for my high-school friends in the mid-1980s to listen to Glenn Miller and Cab Calloway. But it's not.
I am definitely younger than you but am reaching the age where it seems like people give up on new music and decided a few years back I never wanted to say anything like your comment in my life. There's so much new music out there that at worst it will become a discovery problem in old age.
My strategies so far are first to always have an open mind to any popular artists I am hearing for the first time and to not completely write them off if they remain popular. Adele isn't for me but there's no way to say she's objectively bad. On the other hand constant recommendations for Black pink opened me up to KPop.
I also have become ok with not being among the first fans of someone and also being ok with people having different taste. Seems like there are a lot of people who make music their personality, look down on people who like new or different styles that they have decided are inferior, and then when their preferred genre or style stops being popular they just give up. If someone is really passionate about something different it's usually worth giving it an objective shot. I take all recommendations from friends and especially younger people seriously.
I also am lucky that a lot of the music I like works really well in DJ sets. I grew up listening to rap, which always allowed me to hear various artists. I'm glad I grew up in the mid Atlantic and never had the false pressure to say one region made better rap, and was able to appreciate songs with intricate wordplay as well as songs that are just meant to be bangers where the words are just there to help the song flow.
In college it was an easy transition to genres like Baltimore club and its variants. At the time I thought they would replace rap instead of rap evolving and Jersey club being incorporated into the larger EDM scene. That transition opened me up to the massive number of DJs making some kind of electronic music of all kinds of various types.
No clue where my journey will take me, but I know there's no feeling like hearing new music that you just really like. Just today, got to experience that feeling watching an ISOxo set.
I plan to be on that journey for the rest of my life.
And I say this as someone whose favorite time in popular music IS the mid-90's. Many of my favorite albums are from that time.