Bic lighters are a brilliant piece of industrial design. Their irrepairability and disposable nature is clear up front and all part of the deal.
I think the analogy transfers to carbon frames - but really, only a little bit.
Here's the thing - carbon is light and comfortable, but you are *so* likely to change your carbon bike before it deteriorates because of age. Plus, people tend to tell you about the short life of carbon when they are either trying to sell you something else or more likely trying to reassure themselves how clever they were to buy a mithril frame.
Me - I have titanium bikes and zippo lighters. You do what you like, doesn't bother me much either way. I hope it works out OK for both of us.