Streaming is no replacement for a physical music library.
It’s not only that a lot of good music is not on streaming: music also get removed. I have a smart playlist that gets automatically populated with songs in my library that are not available (evidently pulled from Apple Music), and it is growing with tunes that I like and that are sometimes impossible to find elsewhere. If I had the foresight to get actual copies, I could still listen to them.
You can stream from your own not-physical library though. Which is a great replacement for a physical music library.
My "Random Singles" Youtube playlist created in 2006 is approaching 1500 tracks. ~200 of them are hidden, because the video is no longer available.
It's not that I can't find other copies (although in some cases I literally can't), it's that the information has been deleted from my records. My exocortex has had a scalpel remove something, and no amount of backtracking and process of elimination is going to restore it at this large-N corpus size.
I was able to back up what was still up a few years ago, so there's a hard drive in my closet with some of it. But if I tried that at this point, Youtube is pretty determined to fight me with IP blocks.