Spotify prices are quite reasonable, especially when you consider what has happened to video streaming services like Netflix. Plus Spotify has a large portion of all music ever, and mostly has close to 100% of new music that is being released.

Hosting my own, even though it appeals a lot to me on principle, just would be either too costly to maintain legally (buying new music) or too cumbersome illegally (torrenting any music I want to listen to).

I guess if someone is really into music, they will spend a lot of time on finding new music, and will be inclined to spend more money on the hobby too. But for casual listeners like me, it's far too convenient to simple select a song on Spotify and click "play radio" and get an unending playlist of new songs.