Songs and artists usually disappear from Spotify for a number of reasons, such as:
• The artist or legal owner has removed them
• The music license for that track has expired
• The song is not available in your country
• Spotify has removed the song or artist for other legal reasons
However, just because a song disappears from Spotify doesn’t mean it’s gone forever, with songs and artists sometimes re-added or re-instated, depending on the situation. However, you often won’t get a notification if a song or artist has been removed or added, so you’ll have to search for them if you’re looking for something specific.