I think "Missing" is a pretty poor choice of word for this; "Presumed lost to history" would better explain what's happened - Which is both incredible and terribly dull at the same time! Somebody connected the dots on the provenance of a quite old painting that was venerated, but perhaps not as much as it should have been, not far from it's last known location - At least in distance, if not time. Great detective work…
It’s that fourth quadrant of “don’t know that you know.”
I suppose that people in different fields are already using ambient or latent information from public websites for arbitrage opportunities. Glad it was a Sotheby’s provenanceer in this case rather than an art thief.