I don't think my bikes are the lightest of the light but more than one them weighs in at a touch over 20 lbs with the pedals, or over 19 lbs without - (the way modern bikes are quoted). I don't abuse these bikes but I am sure that many of them were ridden hard and put away wet in their past lives with other masters. Nothing of mine has ever failed catastrophically. I've worn out a derailleur or two, many chains and one sleazy Campy Copy seatpost slipped endlessly on me so I tossed it. I've torn some seats and broken many spokes but the frames and parts for the most part hold up year after year.
If the modern stuff actually comes with disclaimers and warnings that they must be replaced periodically or treated with inordinate care such as lube type and exact torque settings, then in my opinion they are not going to go the distance. The Trek web site is filled with precautions such as to warn owners of cf frames that the internal breaks maybe invisable and very dangerous. I have seen these invisable breaks turn into shattering messes first hand. I have also witnessed by way of the classic rendezvous, a DeRosa frame bent into a frightening mess and recently massaged back into perfectly usable condition. That aint happening with cf and you know what? .... I won't be crying over the loss of these modern wonders either.
Garth Libre in Miami Florida USA