For my own photographs I agree with you completely Roger. Rarely has image quality been a limiting factor for me. I have equally (un)satisfying photographs taken with a cosina 50mm, olympus zoom, various canon fd lenses, and my current lenses (sonnar ZM and 35mm biogon c). Using "objective" criteria, the image quality maybe vastly different, but I couldn't care less. I really enjoy using my current camera and lenses, and this really my photographs. This is something I believe no quality enhancement could achieve.
As for photographs taken by others, image quality is a non-issue for me. Either I am drawn to the photograph or I am indifferent.