I guess that can happen but if you own the music, Apple has a record of it
If my personal Apple music library gets wiped out somehow, i can just re-download that music via the app
If I purchased MJ Thriller back in 2011 on iTunes, its in my library FOREVER
I can download a copy of MJ Thriller to any computer or phone I'm signed into
If you are talking about all the music I downloaded since the late 90s from Napster to torrents, thats already backed up on my hard drive, I've uploaded all of it to the Apple cloud and Apple tries to match it to songs/albums already on Apple music, sometimes poorly of course
If its not on Apple music, like all the mixtapes, randoms, etc, Apple uploads those songs/albums to your cloud
If the cloud explodes one day, I still have all those songs on my hard drive anyway
I got 3 iphones, 1 personal, 2 work
my personal and 1 work phone is signed into Apple music with my account so I have access to everything I've uploaded to the cloud and everything that exists on Apple music because I pay the monthly fee ($5 with my college edu)
the other work phone is not signed into Apple music and it just has music directly from my hard drive on it meaning I have to connect it to my desktop and via my iTunes local library, copy music over to that phone manually
all those boogie man stories about iTunes were all fake news