It's more than that though. Some people think that having a high resolution sensor (high pixel density) is a licence to crop heavily and, while you might get away with it for low ISO well exposed pictures, that luxury diminishes as the ISO goes up. But also for heavier cropping you need sharper images, so that means better shooting skills and better glass too - unless they were excellent to begin with.
So apart from good exposure technique you need to pick the right shutter speed for control of shake/blur, the right aperture to control DOF, lens IQ and diffraction and to make sure your AF is calibrated perfectly and that your focusing and general photography skills are all up to snuff. Cameras with low pixel densities conceal some of these blemishes, even when viewed at 100%, but the 7D and its like don't suffer fools so easily when pixel peeping.
There's also something more that comes out of all this. If you shoot sharp images to begin with then they won't need much more sharpening further down the line. And if you're not increasing sharpening much then you won't be exaggerating noise much either and you won't need in turn to apply a heavy dose of NR which will then rob the image of detail. But, shoot a soft image to begin with, with a bit of noise to boot and by the time you've fixed up one problem you'll only have made the other one worse as well. It's ever decreasing circles.
So good results is about more than just the camera. It's the lens, the light, the photography and the processing all pulling together to achieve the best results technically. And then you've got all that creative/artistic aspect to consider on top of that. The camera is just a tiny part of the overall equation. Sure there are some bad copies out there, just as there are bad lenses, bad photographers and bad light. Just make sure the blame for disappointment is laid at the appropriate door.