That's not completely true. Very few images end up poster size on the wall — most end up printed at "normal" sizes or perhaps just in a web gallery. Under those conditions, a great image shot with an "ordinary" lens on the D800 will, when downsized to normal size, be a great capture.
Echoing Mick's comments, I can think of several "name" pros who shoot with bodies from the lower end of the DX line and use the kit zooms. And they capture images that most of us drool over.
Jon Kandel A New York City Nikonian and Team Member Please visit my website and critique the images!