Hello @ckmackey and welcome to the community,
The availabilty of music on Spotify is up to the artists and/or their labels (or rights owner).
Neil Young decided last year to remove some of his albums from streaming service.
Spotify wants all the music in the world to stream and works hard daily to try to convince artists or their labels to have all their music available in streaming.
We can hope that in a more or less close future, it will be the case for every artist.
Help others find this answer and click "Accept as Solution".
If you appreciate my answer, maybe give me a Like.
Note: I'm not a Spotify employee.