I think you have pointed out the main (probable) reason why the 168000 is in the same price range as the 16800: first it is a "saphire era watch" (so lots of "plexi" Rolex collectors are not interested) and there is no "sexy" thing on the dial to look at, like a red writing or a double signature (Tiffany, Serpico,...).
Same thing with the TOG ref. 6202: the first toolwatch made by Rolex in 1953 should be the most sought after Sports model...but it is a little small and does not carry a magic name on the dial like Submariner or GMT Master...
Jeff