Minh, he is implying that the same thing will hold true for WGF--if its only for Longhorn, nobody will use it.
I think he's partially right--I wouldn't try to ship any software for mass consumption using WGF if it was only available on Longhorn, though hobby-stuff may just do.
Ahh, re-reading the post, you're right. It occurs to me that Longhorn will also support DX9, so we can always stick with that. I wonder what the motivation behind WGF is. It seems distinct enough to discontinue it from the DirectX line. I wonder if this is
MS's attempt to "do it right". In which case, developers should rejoice (after the shock of learning yet another API). Programming should be easier, then, with WGF. Well, onward, I guess.