Those numbers have no context. The only way they really mean anything is if each of those climbs by each of those riders was hit at full gas and alone. On Alpe d'Huez, Lemond and Hinault in 1986 for instance had a big gap on the chasing riders and agreed to ride together. Much different than any of Pantani's or Armstrong's rides up the Alpe. How much faster could either of them have gone if they had/wanted to? Who knows? Also note that those two got away on the previous climb and had been out front working hard for a while before they got to the climb. On the other hand Armstrong and Pantani for the most part got free rides to the bottom when they raced it. I can't remember Indurain's ride(s) up the Alpe, but I suspect that he had more of an armchair ride than Lemond and Hinault, and probably needed to ride the Alpe hard to either follow attacks, try to take time, etc.
Here's another data point to throw it all out of whack. I rode Alpe d'Huez this summer. Full gas and alone. 50:55 on 340 Watts. ~40W less (though I was closer to 74kg) and almost 3 minutes slower. So, a 49 year old amateur racer was only 3 minutes off of Lemond's time on Alpe d'Huez and you're going to use Lemond's time as a comparison against other riders???? I don't think that is going to compute with your model. In fact, I can pretty much garauntee that Lemond/Hinault's time was not fast for them.
Check this out:
Timtoo timing
Other than Sandy Casar, it's all just a bunch of dorks like me who took the time to rent the timing chip. Seven of them went faster than Lemond/Hinault. Does that make them virtual Tour champions?