People want to imagine that the simple use of carbon fiber here was the sole mistake, I guess because it's easy to understand and makes us feel smart. But come on, engineering is harder than that. Carbon fiber pressure vessels have a long history. Composite material failure modes are for sure more complicated than metals but they certainly aren't a mystery. We've been using composites for more than half a century, we know how they work.
No, my gut says the root cause here (if we ever find one[1]) is going to turn out to be a more routine kind of engineering fuckup. It'll be just some weak point that the analysis failed to turn up.
[1] And sure, if we don't then the "carbon fiber death cylinder" theory will just become part of the folk truth, I guess.