They identify a huge surge in tracks that few listen to after gen AI started.
The analysis is worth reading. The distribution is (Pareto)^3 ~99% of the tracks played are 1% of the catalogue.
First off, it was striking to me how little of the "top 10 000" they published back on Christmas I recognize. I'm not sure what I expected, but 10 000 sounds like a big number, so it seemed likely to me, that if I get a random song from my playlist I could find it there. It turned out I hardly can find an artist I recognize. Ok, I can recall a song from Lady Gaga and even Billie Eilish, I've heard of Bruno Mars (cannot recall any song), but I have no idea what is "Bad Bunny", "Doechii", "Drake". I mean, I think I do have a pretty good idea what these things are (abstractly), and I probably wouldn't want to listen that. And while I knew that all this stuff is very popular, I didn't quite realize how little place in the top-10000 it leaves for the music I (and everyone I know) actually listen to.
I didn't download the metadata they released (it would be hard to process it on my laptop anyway), but now I wonder how much of my 3 TB music collection is in top 100 000, or heck, even top 1M Spotify, or on Spotify at all.
I also am sometimes surprised how little scrobbles some tracks get. I didn't bother to find out what this means, how many people still scrobble to Last.fm or ListenBrainz, but it is just surprising when I see that a track that I didn't consider to be obscure was scrobbled like 50 times this year.
So I'm saying that music worlds seems to be terribly fragmented, even more than I imagined. So the very premise of AA backing-up 97% of Spotify (by the number of plays) may be much lesser achievement at "preserving culture" than it may sound. And of course we are about 8 years too late to backup everything, since by now half of it must be generative NN bullshit. And I'm not even sure it's in those leftover 3% (bots listen to bot-generated music too, right)?
I've heard of 9 of the top 10 and 15 of the top 20 at https://chartmasters.org/most-monthly-listeners-on-spotify/
You might not listen, but surely you have heard of Taylor Swift, Justin Bieber, Ariana Grande, Ed Sheeran, Coldplay and of course Christmas Staples of Mariah Carey and Wham?