Oh, I don't. I still think the overwhelming majority of the cycling population is not pushing a 20+MPH pace for three hours. I just looked up the results of the last organized ride I did, a Giordana Gran Fondo Series event in Ontario, the 100k category had 10% of folks finish at or under three hours (25/255), and 69 out of 255 finished above 4 hours. Mean average was 3:42, median average 3:43.

Put me around that four hour mark, toss in some cleanup and recovery time, and yeah, it is using up a large part of one of two days I have off a week. Not nuts at all, just harder to do when your limited time gets spread amongst other things.