This is true and a category of music that got hit notably hard was live recordings. What had a wide array of live recordings made by sound engineers straight from the mixer. This is something that you simply cannot find now unless you maybe know a guy.
That's why I use YouTube Music as my streamer as they allow damned near anyone to upload any old rare record and then figure out the royalties somehow.
FWIW archive.org has a lot of live music as well