The only reason I don't pirate music is because of discovery. I haven't found a good way to find new music without using a streaming service. And then, I'm already using a streaming service, so why bother.
This. Back when I was a spring chicken I had nothing better to do with my time than download random songs and albums. Ain't nobody got time for that now.
Streaming is fine to discover music, but you are not guaranteed that an album you like will be there for you the next time you want to listen to it. I do listen music in Spotify with a modded app, then I download the albums I liked. There are albums that I can't listen to Spotify anymore, but I still have the audio files in my Subsonic server.
Sure, it's easy to download one song. But I watch maybe two movies a month, yet I listen to thousands of songs in that time. Downloading songs individually doesn't even come close to the convenience of streaming. Not to mention the lack of music discovery and social features.
There's different ways to automate it. There was a thread a while back where someone outlined their system. He kept the free Spotify account and had a script that checked it every week for his new recommended playlists, then it would download it automatically. He used an other software to host the library.