I like to say that the difference between tourists and randonneurs is that randonneurs aren't sensible enough to stop for the night.

The way I see it, a touring bike has to handle fairly heavy loads. Thus a good one is a fairly heavy bike. In contrast, even in winter I carry less than 10 pounds on my rando bike, it doesn't make sense to have a beefed-up bike for randonneuring. At this point, I would say that randonneuring bikes are in fashion among the general public more than they are among randonneurs. Seems to me that something like a Specialized Roubaix makes an excellent randonneuring bike.