2012 - a lot of new Nikon DSLRs released, 2013....

No it isn't, it's not the same type of camera, it just happens to have a better sensor than the D3x, which is to be expected 4 years after the release of the latter. The D800 is the successor to the D700; body, name and price being unmistakable hints. The D3x' successor will have the pro body, cost 2-3 times the price of the D800 and be named D4x.