I wonder are you talking about racers or recreational riders?

The recreational clydesdale riders I know who ride high end bikes may love the fact that they (the bikes) are light, but it is the perceived quality, performance and/or comfort that sold them on their bikes most often.

In other words, the motivation for a weight weenie to buy a CF bike may be the saving of a couple of pounds in the frame. For a big guy, I think, it is as likely as not the more comfortable ride or the perception that it is a better, more aggresive, etc. bike.