Interesting thoughts Bill.
For me the threshold is more about content than, to put it simplistically, resolution and perfect sharpness.
For the shot you present, the formality & setup would have lent itself nicely to a 4x5 negative. That said, the shot works for me as is, simply because of the content and fuzzy presentation.
The best way I think I can put this is that memory isn't always sharp and the fuzziness places a marker in your life's timeline. The photo "fits" the story.
I think this is one example of why I lean "Pictorialist" rather than f/64.
Even with new work where I want sharp subject matter, I don't want the context that the subject matter sits in overly defined. Life isn't that well defined and I want to let the viewer fill in the blanks from their history.
Too much clarity makes me ask myself technical questions (Where? What film? ...) instead of connecting emotionally.