Okay, I'll bite.
There seem to be a lot of people on both sides of the spectrum that seem to have absolutely no idea what they are talking about....a lot of generalizations here IMO (but take what I say with a grain of salt as well).
Now, i'm not going to comment on the WS100 or any 100 mile ultra as I have not run that far myself - however, I will say from having some experience in a variety of different events from the track 1500m to SkyRunning events like Speedgoat to Transvulcania and more runnable trail ultras like White River and Lake Sonoma (as well as having raced all these mentioned guys) that what really matters is the course profile.
Throw VO2max and velocity at Lactate Threshold out of the window...that doesn't matter very much. (Killian's may, but only because he does a lot of high altitude stuff...). I saw him suffer at UROC and he suffered better than me, but the desire was there early on to try to win the race...
No, what matters most IMHO is Running Economy on specific terrain. There is a certain thing to be said about running on smooth dirt trails and running on rocky steps in the mountains. Percent grade and steepness of every climb matter. The duration of the ups and downs and how long they last and when they occur over the distance of the race matter a ton. The course determines a lot on whether or not a sub 2:25 marathoner can really smash a course or if they really may blow up. The course profile (not the distance) determines a lot! At Speedgoat there is going to be a 25-30% grade climb (off trail up Mt. Baldy at 11,000' for about a half mile) that i'm going to have to "power hike" up and it's going to be very slow going for me because I suck at that kind of movement pattern. It's not a movement pattern specific to fast road or track running...
Then there is the metabolism issue. Some guys are better at burning fat and sparing glycogen than others. Some guys can eat a ton and not have stomach issues. Sometimes these races are a fricking eating contest!
So having some raw speed and having a high Vo2max and velocity at Lactate Threshold effort helps give you more aerobic reserve...but in the very long runs if your stomach isn't solid, and if the muscles in your legs just fail from all the climbing/descending...then that's not going to matter much when you have 20 or 30 miles to go and all you can do is wobble along at 8-10min mile pace (if even that). Factor in altitude in a lot of these SkyRunning and mountain running events and there are more variables at play...
In regards to my performances not being as solid this year... well, there are a lot of things I'm still trying to figure out in training (mixing in an ultra nearly every month with road races like Mt. WA and the Carlsbad marathon is not ideal and I know that!). I've only been doing about 80-90mpw for most of these things whereas coming off of college and Hansons I was in the 120 range a lot doing some decent track workouts. I think there is something to be said about generating muscle tension at 5:00min/mile pace and boosting Vo2max - but on the flip-side if you can't climb and descend rocky/technical trails for thousands of feet at a time then the legs fail first in ultras (way before the glycogen stores do). But then again, it depends on the course...
So there is a movement happening in the sport with more guys and gals who have track and road backgrounds entering the the scene. This is what my "MUT Runner" film is about and I'm glad I've interviewed runners like Max, Rob and the women's WS100 champ Stephanie Howe. What does this mean for this niche of running? Well, I think it means that a lot of course records are going to go down! I can tell you for a fact that my course records at White River and Speedgoat are soft. There are a lot of guys that can take those times down by quite a bit (i.e. sub 5hrs at speedgoat, sub 6hrs at White River). Lake Sonoma (set by 31min+ 10km runner Zach Miller who beat Rob Krar and I head to head this year) is still soft. In the future, the top runners in these Mountain-Ultra-Trail events will finish closer and closer together IMHO.