Virtually all of the day hikers that we met at the portal and on the trail didn't make it.
Lots of day-hikers make the summit. My wife and I did it in 1988 with less than a year of hiking experience. I tagged Mt. Muir on the way up, we took a nice break on the summit, and we were back at the Portal in around 13 hours.
My most recent day-hike on 1-13-14 was under 13 hours.
