I guess people still mistake who those cameras are meant for.
5D3 + new 24-70 f/2.8 + 70-200 f/2.8 IS2 = best low-light shooting equipment available. No conicidences that Canon has also updated its speedlites and there is talk about new 35, 50 and 85mm L-primes. All is meant for wedding/concerts/events pros. Apparently Canon is giving priority to this segment, hard to say if it is exactly what they wanted or just the best they can do with what they have.
D800 is much more an all-rounder camera with better specs but yet cheaper, which is why it feels so "better", or at least surely a much better bargain. That said, it is also right to consider that D800's pumped-up specs leave room for a very decent entry level FF camera, while you can't downgrade the 5D3 that much and still make it look attractive.
I don't think there's anything new here. Nikon keeps doing better cameras, Canon keeps doing better lenses. Probably I'm over-simplifying, but in the end it comes down to this. I prefer a worse camera and a better lens, so I stick with Canon. To someone who can't afford L-grade lenses, though, I would advise Nikon with no second thought. Anyway I have the feeling that the D600 will be such a bargain to make me (and many more) seriously consider a swap.