It's just not something the competition has been doing, and I suspect it's largely out of self-preservation rather than a lack of ability. Sleep deprivation is not particularly good for the brain.

Now that Courtney has demonstrated this strategy, and how impossible it is for even the fastest of distance runners to beat it if they sleep, I expect ultramarathons to become a bunch of sleep-stumblers after the first day in the future.

Which makes it not really about distance running anymore. It's more like a run followed by a long tired hallucination-ridden hike.