Julio, in the interest of giving it a try I gave it a try. : )
I tried, again, a variety of tools in Paint Shop Pro. I started, at your suggestion, with an edge-finder (a colour one rather than a monochrome one) and softened some of the strongest lines. I successively desaturated, softened, warmed, "Clarified" (a PSP tool that changes local tonal relationships), and cloned some specific bits (like the faces, necklace and parts of the man's coat) back in from the colour edge version. I tried reducing noise at one point and that introduced a lot of those cross-hatchey bits especially in the lower half. I burned in some parts (the man's coat and the four corners). I liked the smudgey, dirty look I was getting, as if the print had been stored in a damp cupboard for twenty years. I brought up the tones again (warming slightly) and tried some selective sharpening and softening.
This is the result:
I still like yours better! Among other things, mine suffers from too much cross-hatchy stuff and too much latter-step softening (which gives it a patchiness like looking at it through wet glass).