Okay, forget that, and I'll just condense my point. Of course 5.1 has better quality and let's developers do more. The thing is that most consumers don't have the audio equipment to get the most out of PLII. So 5.1 for most consumers is out of the question as well.
That is why Nintendo was in no rush. Same reason as HD graphics.
As for the format going away, it might, but popular or widespread formats go away when they are either obsolete, no longer bought by consumers, or too cost prohibitive compared to something new. The obsolete reason makes sense, but not consumers (since it's included in systems, not something separate), and certainly not cost, since games on the PS2 used PLII (5.1 was only available for DVD playback), and they didn't cost to much to make the audio.
So when the costs for higher formats become negligible over PLII, then PLII will go away. Not having the best sound is not a reason to get rid of it. Heck, some artists look at limited tools as enhancing their work*.
Again, as long as it's not cost prohibitive. The limited size of the DS doesn't really scare developers, unlike the N64 carts.
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs
