Perhaps the problem -- if you believe what Cory Doctorow has to say -- is that there aren't enough masochists in the world to make for a legitimate target market (for anything, not just Zune).
You were a sucker if you bought MSN Music tracks. You're a masochist if you buy Zune tracks.
Cory got the tip from Brent Lord who got some news from News.com's Ina Fried that Microsoft's MSN Music is officially shutting down. Big deal you say? Well, maybe not if you didn't buy any music from the MSN Music Store. But just supposing you made a big investment there and want to keep using those songs (legally), you must (from here until eternity) make sure you have a PlaysForSure-compliant playback device. The problem is that the future of the PlayForSure ecosystem is unknown. Now that Microsoft is launching Zune, it's conceivable that PlaysForSure (incompatible with Zune) will share a grave next to Bob in the Microsoft graveyard at some point in the future... thereby stranding not just MSN Music Store buyers, but also people who acquired or subscribed to content from one of the other PlaysForSure-compliant merchants (F.Y.E., Napster to Go, Real, Yahoo, etc.).
This Digital Rights Management-induced nightmare is the the same one that has future-oriented librarians worried sick. The scenario they most fear is where important historical works are stranded on their shelves because the proprietary hardware and or software needed to open them up no longer exists.