I think he means Kestrel bikes, not carbon bikes in general. I wish I could remember the site, but there was a test done on some carbon, steel, and aluminum bikes to test for longevity and I believe the Trek, Cannondale, and one other frame managed to make it through without any breaking point, whereas a lot of the other steel and aluminum bikes failed. I wouldn’t worry too much about the durability of carbon as it’s proven to be pretty study since it’s introduction.