Whether carbon bikes & associated components become C&V worthy 20-30 years hence has more to do with esthetics & collectability than durability, and the demographics of the collectors. Durability is a question, with the possibility of hidden damage when a bike is resold years later. But carbon is pretty tough, and troubled products like forks have been recalled & removed from the market.

Modern bikes, though, seem to have a design style based on how many logo decals they can put on the frame and wheels. They are, for the most part, mass produced in China or Taiwan. They may be great bikes technically, but I don't find any art or craftsmanship in them.

The stereotypical C&V afficianado is a middle aged guy who either still has, or wants to get, the bikes he rode and lusted after as a teenager/young adult. It helps they are easier to work on, plentiful, and relatively inexpensive.

The current market for new road bikes is expensive and stagnant, and fewer young people are cycling. The manufacturers know to increase sales they have to sell older riders multiple bikes by rapidly obsoleting them. So look ahead 20-30 years. Will a young person who perhaps idolized Lance and saved his money to buy a Madone want one when he's 40?