There is a exploded view of a Pelikan 800 at the top of the repair forum. The barrel itself is clear or tinted plastic, with a nose piece sticking out that the section is glued onto. The striped part of the barrel is called the binde, which is glued on over the barrel itself. Last I heard Pelikan charges $250 for a replacement barrel when the pen is out of warranty.
I don't know how many fail VS the number of pens sold, but I repair an average of 3-4 of the pens a month, and have for nearly a decade. In most cases the nose piece snaps off, leaving the forward part in the section. Sometimes it's a clean break, sometimes uneven. Yours is one of the more extreme cases that I've seen, where the binde has come off as well.
There is an awful lot of stress in this area as you write. Given how they break, and how often I see them, I don't think that just solvent welding the pieces together is adequate. I machine a bushing to bridge the break, and machine barrel and section to fit, then bond the pieces together. I have 4 of them that I've done and use to test the durability of the repair. Thus far, none have broken in the repair area. Barrels have broken if stressed enough, but always somewhere else. Thus far, none have come back to me because the repair failed.