The reason is that the parts will most likely stop being available a few years down the road. How long does a carbon fiber frame last if it's ridden constantly from day one? 5 years? Ten? It seems most bikes now are made for the moment, not so they will still be ridable 30 years from now. Set a CF bike beside the garage
for 20 years like most of the steel bikes I find. I surely wouldn't trust it further than I could throw it. Twenty years from now I will probably not be able to throw it very far, despite it being light, hehe.,,,,BD