Assuming Spotify signs artists (or Apple for that matter), will they be willing to upfront costs against touring, recording, production? How would they structure recoupment? Apple could structure a better deal because they can cover mechanical royalties through download purchases. Spotify would be streaming only. The economics would be very, very tight.

It'd be hard for them to do a 360 deal to get revenue from the money making aspect of music (sponsorships and live), unless they also staffed up artist development (touring) and sponsorships/partnerships/biz dev.

Its not as easy as just "signing an artist"

If it was, we'd have already been disrupted by the indies.