My amateur view is that carbon fiber seems like the wrong material for a vessel meant to resist outside pressure rather than to contain inside pressure. That’s because the fibers would tend to be under compression rather than tension, which doesn’t seem to play to their strength so to speak. Don’t know if that’s a valid analysis but it’s what comes to mind first.
That is my understanding of was written also.
It also explains the supposed NASA connection. Someone did design the hull to withstand pressure, just an entirely different type of pressure and for an entirely different application.