>>1705506Probably partly this. Also, ultrarunning has become a fad, and trailrunning is just a more challenging and enjoyable form of ultrarunning. People are also severely neurotic and self-absorbed so they feel the need to prove to themselves they can do x.
The way to know your answer is not 100% correct is that the UTMB is still growing in popularity and has morphed into a disgusting consumerist nightmare with literal crowds of people lining the trail on large sections of the course. But this isn't stopping more and more people from coming each year. Then again, you do see some of the elite athletes shying away from the UTMB for this exact reason. Kilian Jornet used to live in Chamonix, but moved to a remote part of Norway where he can ski and hike without retards disturbing him. He's also mentioned not being a fan of the excesses of that event. At least American trailrunning is still quite lowkey in comparison.