I think it's obvious to MusicMatch that they'll be losing Apple soon. Apple has made no bones about the fact that they're working on iTunes for Windows. Though I haven't heard Steve Jobs come out and say it, I'm laying odds that Windows iPods will soon make the "switch" from MMJB to iTfW.
So, from MMJB's point of view, who cares that you can't use their new store to stock your iPod? They've already lost the iPod contract, so they're focusing instead on all of the other portable players that come bundled with MMJB (many of which support WMA), along with all of their OEM contracts.
I browsed MMJB's new store. Looks, feels, and plays just like the iTunes Music Store. There will most certainly be a long line of copycats; it's a great model for some, and about damned time consumers started to see something other than litigation from this industry. That's a totally different rant, of course.