This is a truly elementary and uneducated question, so be nice please.
I have seen (and touched) a lot of top-end frames in the last two weeks. And one thing strikes me about many of them. To wit, the tubing on metallic ones - mostly the Alu ones - sounds like it is paper thin.
I know that is a bit of an exaggeration, but practically, doesn't one run a lot more risk with that kind of frame in everyday use? It seems to me that just dropping a helmet on the top tube, or virtually any kind of crash, would write them off.
How much unintended punishment can they take? Is it possible to have a single tube replaced? That would require a new paint job as well, but many of these frames cost in excess of $2K, so the repair price could pale by comparison to buying a new one.
Of course, if the team provided it ...
Cheers...Gary