Just looking at the UTMB results in more detail. It really is a different kind of race. This year there were 1088 drops and 1468 finishers.
Two-time women's champion Rory Bosio was a DNF, as was Andy Symonds, who set the course record at Lavaredo Ultra Trail in June. Many elites were on the DNF list, including Didrik Hermansen, the 2015 Lavaredo champion.
The eventual winner, Ludovic Pommeret, was in 50th place after 40K with stomach problems that had him thinking about dropping out. He finished in exactly 22 hrs with a 26-minute cushion over 2nd place. Moral of the story: Don't give up!
The iRunFar summary is here.
Andy Symonds draws cartoons in his race reports. Here's one from his UTMB report. He dropped at Champex Lac at 122 km - the same place I did. Click on it if you want to see it bigger.