You are comparing image degeneration due to over-enlargement. I'll agree that degeneration of film is often more acceptable than that of digital capture, but this has little if anything to do with normal use and practice.
... but what does who call "over enlargement"?
Film got better over the decades, but prints ten times the dimensions of the film was the normal yardstick for fine grain film, giving 22.5 inches for 6cm MF.
For AA-free MF digital I consider 360 original camera pixels per print inch ideal, which gives 18.6 * 24.8 inches for a 6708 * 8956 sensor.
According to these figures, the 60Mpx H4D-60 (or P65+) is equivalent to 645 film... but many people are saying that AA free 60Mpx is equivalent to 10 * 8 film.
I suppose that I am talking about more detail than the naked human eye can resolve, and less degradation/grain/noise than the naked human eye can see... but is this not the right yardstick for "optimum" prints?
People selling 60Mpx cameras (and I) might use these figures to justify investment in 60Mpx kit for 18 * 24" prints, but, since the birth of digital, users and sellers of low-res cameras (and the high-street print shops) have been trying to convince people that res as low as 72 ppi is adequate.
Painters generally think it acceptable for the observer to see brush strokes in a painting, and most photographers (and buyers of photographs) think it acceptable to see some grain (more so than) diffraction|digital noise... but I want pictures to look like the scene seen by the artist.
...but you only need enough res to resolve the detail in the picture, which is why low-res misty scenes are popular with landscape photographers.
...but then, of course you can try to filter out haze, and light up dark corners, and produce pictures better than what the artist saw!
