Why is that? Resolution? Really? Resolution is 99% hype. It does nothing at all for image quality. A good photo at 12mp is better than a mediocre photo at 36mp. And is THAT fact that most people either do not understand or do not want to.
Resolution is not hype. It's clearly defined in terms of 'line pairs per millimetre' (LPPM), or sometimes 'line widths per picture height' (LW/PH) at 50% contrast.
It's a fact that a sensor with a higher pixel count is capable of delivering higher resolution from the same lens. The only hype would be to assume that such increase in resolution is proportional to the increase in pixel numbers, that is, it would be an exaggeration to claim that a 4x increase in pixel numbers on the same size sensor is equivalent to a doubling of resolution. It's likely to be a bit less when one uses the same lenses.
If, by a 'good' photo, you mean an artistically pleasing and interesting photo, then neither resolution nor any other performance characteristic of the camera can ensure that. But even so, one usually needs a certain minimum level of camera performance. There's not much point in having a wonderfully artistic shot of a feathered bird sitting on the branch of a tree if the resolution is so poor you cannot tell what species of bird it may be, or even if it is a bird in the first instance.
If, by a 'good' photo, you mean a photo with smooth tonality and clean shadows, then it's true that increased resolution alone will not guarantee that.
However, in the case of the 36mp D800 compared with the 12mp D700, the D800 does produce smoother tonality and cleaner shadows, in addition to significantly higher resolution.
For example, at base ISO and equal print size, the D800 has over one stop lower SNR at 18% grey. At ISO 12,800 it has about 3/4ths of a stop better SNR, and at ISO 25,600 a whole stop better SNR.
When it comes to dynamic range (or clean and detailed shadow charcteristics), the D800 advantage is even greater. At its base ISO of 100, the D800 has over 2 stops better DR than the D700. That's very significant. At ISO 400 the D800 still retains a 1 stop advantage, which is still significant.
The D800 does not need any any hyperbolic advertising to make it appealing. The facts speak for themselves.
Now, all that remains is for Nikon to contact me and offer me a free D800 for my wonderful promotional efforts.
(Joking of course!)