Now that I've had a little time to digest the news that the iPod already has hardware support for Microsoft's WMA format, I've realized what probably should have been obvious from the outset: this cuts both ways. Any non-Apple player that uses that same chipset is just as close to supporting AAC as Apple is to supporting WMA. All a vendor would need is a license and a firmware update.
Apple, however, has chosen not to license anyone but HP. Needless to say, it will be interesting to see how the market plays out over time. On the surface of things at least, it appears that no one purchasing either WMA or AAC protected music will be left out in the cold.
Meanwhile, I've put an email into Player Portal, Apple's chip vendor. I'd like to get a list of which non-iPod products use their chip and could potentially support AAC.