Agreed. But my point is Kelly isn't that much different from the others except his arms are a bit more vertical. It was Guimard and the '80's that produced really extreme stretch, and Kelly sort of avoided that, so LeMond in his book criticizes Kelly's position, but I don't see it. The human body hasn't changed and guys like Coppi, Anquetil, and Merckx had no problem getting aero.
Starting perhaps with Bartoli there was a counter trend to not stretch out but stretch down: maximum bar drop. That's what Andy Schleck does and it's perverse. He can't even reach his drops in the saddle. The guys with the best position, from Coppi to Contador, look balanced: they can get low when they need to be, but they aren't forced there when they don't.
On Cavendish: he wins because he's explosive, has amazing ability to put himself where he needs to be, and because in the sprint he's consistently the most aerodynamic sprinter there: indeed arguably the most aerodynamic in history at that level. It's not just power which wins sprints, and most sprinters focus primarily on power.
Kelly had his saddle lower than standard compared to traditional fit now. I should have made that more clear. From other pics he seemed more bunched than those posted.