Just a thought about comparing times over years, for example the 5 year gap from 2007 to 2012. I know others have made a similar point, but this isn't Keirin racing where the tech has essentially been frozen in time, the bikes and drive train are constantly evolving, even if there is a minimum weight limit.
On top of that huge variable which makes them incomparable are a host of others. Climatic conditions from everything from air temperature and road temperature to wind strength and direction, humidity, air density etc. The individual parcours of the two stages: I haven't researched but where they identical, so the riders where climbing after the same km, or how about the stages preceding the one we are comparing?
All equals infinitesimal variables which would require vast amounts of quantative data to analyse and compare, and I doubt even with that the results would be a long way short of conclusive.
I have argued before that comparing riders performances from different seasons is hugely inconclusive and this is another massive red herring. Different eras, different riders, different peloton, different weather, different bikes, different clothing, different training, different nutrition, different drugs too.
Cycling is a hotbed of innovation, don't ignore a basic truism because it fits your argument.