Getting back to defining IQ...where the hell did that come in, with the advent of digital or before? I don't know. But it does seem that image quality is defined differently now with the common usage of digital cameras than it has ever been defined.
With millions of fine photographs in the past, including many Pulitzer prize winners, it is incomprehensible that only sharpness, contrast, etc. define the quality of an image, IMO.
Thought-provoking threads are good to keep us thinking but our thinking needs to be not completely free-thinking. It should have parameters defining what we are discussing and so far, I don't think the IQ definition has been agreed upon or, if it has, then I missed it.
And then, there are the subjective opinions as to IQ...I may like (and I do) macro images with 2mm DOF and other may not... I happen to like impressionistic images.