I am 100% against hoarding, but data hoarding makes a lot more sense to me.
I was looking for an album by a small punk band called Straighten Things Out called "Dawn Of A New Hope". Loved this album; listened to it all of the time on Apple Music (where I discovered it). Went on a walk one day and tried to load it...and it was gone.
I can't even find this album on eBay, and you can find everything there!
"Milo Goes To College" by The Descendants, a more well-known pop punk band, was removed as well. Randomly, without warning. The Descendants are often credited as the "fathers" of Pop Punk; basically any mainstream pop punk band you've heard of cites them as an influence. This album basically started this genre...and it's gone.
Fortunately there are enough vinyls of this record that make it easy to find when I one day build my epic vinyl collection.
Had I saved these to my iTunes Library or ripped them to a NAS of some kind, I'd still have it. (Fun fact: Milo Goes To College _was_ in my Google Play Music Locker, which Google sunsetted when they launched YouTube Music, so I lost that "copy". I'm also going to guess that it was in my iTunes Music Library as well, which still exists as cloud storage, but albums that you add to your iCloud Music Library from Apple Music are pointers to tracks in the streaming service which can go away at any time.)