I actually think down the line if they make Spotify non-free, lots more people will hop on board than y'all think. It's $10. People will have had years of listening, libraries of music, and so much put into Spotify, I don't think everyone will just leave. Lots will, but I also think lots will stay so.
Personally me after using Streaming for 3 years, I don't ever want to or feel a need to go back to having to download everything to listen everywhere. That's just so stale. I'd rather cough up a subscription.