Not really, there is a lot missing from Spotify, and not just obscure music. And you have to accept the fact that music may (and does) go missing at any time.
Plus, even for songs that are on the platform, you are forced to listen to what version they have, which is almost always a "remastered" version. Example: early Beatles songs have vocals hard-panned to one side, which sounds terrible on headphones. It sounds way better on the original mono version.
Spotify is a mediocre experience at best for music nerds, which is probably what the person you're responding to is (has an amp and speakers, vinyl, etc).