Why renown photographers use f/16 constantly, I don't know. What I do no is that they throw away some detail. It's a good idea to stop down, if you need to but also a good idea not to overdo it when not needed.
Indeed. I can only guess why renowned photographers would do such a thing, but most likely it's to even out the corner versus the center performance of their lenses, and maximize single shot DOF. There is also a chance that their creative skills exceed their technical insights. Stopping down more than needed will increase exposure time (and thus wind motion blur), and they'll lose microcontrast in the fine details that is unrecoverable.
I've attached a chart showing the Optical Transfer Function (is the diffraction plus defocus limited MTF, assuming a perfect lens) of a D800 (maximum 102.5 cy/mm equals Nyquist) with a Circle of Confusion of 1.5x the sensel pitch. Such a critical CoC will deliver an even sharpness throughout the DOF zone. For a 24mm lens that would give a DOF zone from 1.80 m to infinity at f/22, from 2.47 m to infinity at f/16, and from 3.59 m to infinity at f/11, with hyperfocal focusing.
What the chart shows is that f/22 will sacrifice the maximum resolution of the D800, it will drop to some 74% of what the camera is capable of. It also shows that f/16 only just allows to reach the maximum resolution that the camera is capable of, but with an overall less contrasty image than e.g. is possible with shooting at f/11. Going from f/16 to f/11 will e.g. boost the MTF50 from 43.0 cy/mm to 57.4 cy/mm, and the contrast at the limiting resolution (near the maximum possible resolution at Nyquist) is also significantly higher, a much better starting point for deconvolution sharpening.
The lesson is that going for maximum DOF in a single shot comes at a price.
The Cy/mm resolution also gives a quick indication of the output magnification potential. If we consider an output resolution of 5-8 cy/mm to represent good to high quality, then we just divide the sensor resolution by 5 or 8 and we get the magnification factor . Then magnify the physical sensor size (36x24 mm) by that magnification factor, and that will give the output size. Thus when going for high quality, f/22 only allows a 9.22x magnification before it's output resolution drops below that of the 10.3x of f/16 and f/11, with f/11 giving overall better microcontrast. The narrower aperture shots also need much more (higher radius) deconvolution sharpening to recover from the overall loss of contrast.
Cheers,
Bart