I don't want to listen to the same collection of songs every day for the rest of my life, though. If services like Spotify fail and go away completely, the solution wouldn't be that I start buying music all of the sudden: It would be that I listen to less music, much like I did before these services came about.

If one record company pulls a track, so be it. That track will simply be out of my rotation. If I happen to be listening to popular music and I really want to hear the song, it is probably available other places. If I can't find it, so be it: I'll listen to something else and soon forget about that song. No big deal. In the end, I'm still dependent on the record company making it available in some way or another.