Bringing it back to the root discussion that once you remove the requirement for authorization to copy works, there aren't many ways left to steal IP other than intentionally stealing the authors reputation, which more or less is the full official definition of plagiarism. Which you can do perfectly well by miserably failing to properly document a source, not just claiming you authored it. If I claim I wrote your post, that isn't treated all that differently than if I claim PG wrote your post.

Also muddying the waters is most plagiarism definitions include some level of intentional act, not just Fing up. Negligence is a super fuzzy area. So accidentally citing you as Qubix because I've played the board game is more or less OK. Incompetent, true, but not plagiarism.

Note that SOME people insist on getting all wound up about self plagiarism which can be a fraudulent act, but is not exactly real plagiarism, they just kind of borrowed the name because it sounds evil. Much like the multiple and peculiar definitions of computer "hacker" which have very little to do with each other aside from sounding impressive. Self plagiarism has nothing at all to do with plagiarism, other than both coincidentally being more or less wrong.