Yeah, they said they had an outside chance at a late 2010 release. A lot of things could happen that would delay the release enough to push it 2011.
Next year they have Mario Galaxy 2 as their early year title, Metroid as their big holiday title, and maybe even Pikmin 3 somewhere in between. Add Sin and Punishment 2 and Endless Ocean (at least one of which I believe is slated for next year), and they are full enough that they don't need a Zelda, too.
What I'm saying is that there are enough games to hold us over until 2011, and it gives them more time to try and create a definitive Zelda experience.
# of games above 75 on Metacritic (including downloadable):
360: 241 DS: 144
PS3: 152 PSP: 126
Wii: 85