Just because situation is better doesn't mean it can't be further improved. You're considering 'No Spotify' vs 'Spotify' instead of 'Spotify' vs 'A better Spotify'.
If you think on principles, Spotify should in the long term aim for maximum customer satisfaction. This means optimizing the satisfaction per customer instead of per music play, seems to be currently done. By concentrating money on bands each user listens to each of those bands (getting more money) should theoretically improve in quality (and give Spotify more attention), increasing overall user satisfaction. It's a simple reasoning.
Never mind the fact that it's just plain wrong to assume that "those bands NEVER used to get airplay". E.g. there are a number of significant artists on the label Drag City, such as Ty Segall and White, both of which get plenty of radio play, and most of the label's catalogue is not available to stream.
If you think on principles, Spotify should in the long term aim for maximum customer satisfaction. This means optimizing the satisfaction per customer instead of per music play, seems to be currently done. By concentrating money on bands each user listens to each of those bands (getting more money) should theoretically improve in quality (and give Spotify more attention), increasing overall user satisfaction. It's a simple reasoning.