Would Apple see more sign-ups to MobileMe if it were free? Undoubtedly, but lowering it from $99/year to $20 will still be advantageous for them. That's if these latest rumors are correct. The cloud-based "back-up" service we last heard about has been mentioned again, and is beginning to sound very likely.
Instead of streaming songs like Rdio, Rhapsody and Spotify, Apple's "music locker" (as it's been dubbed by those in-the-know) would back-up individuals' songs downloaded from iTunes, so they could theoretically be downloaded again for free to individual iProducts, instead of syncing them. [The Music Void via 9to5Mac via BusinessInsider]