It's less about originality than crediting sources.
If I restate something using completely my own words, I'm still supposed to cite the source where I got the idea.
If something is completely my own invention, and I didn't use any sources to create it, then that's original and I don't need to credit anyone else. But that's very rare.
how do you account for the compilation of your insight that was formed through the consumption of many prior examples? do you feel compelled to thoroughly cite them, or have they crossed a threshold marked through your ability to now generate new similar things without directly referencing them that it's "all original you" now?
If you're writing an academic/research paper, you still have to find something to cite.
"I know this stuff, just trust me" isn't a valid citation. The point is to give anyone who reads the paper a way to a) verify that each fact you put in the paper has solid academic sourcing, and b) find more information about it if they wish.
If you know a lot of stuff about the topic already, that's great—but unless you've already written and published papers on the subject, you can't just cite yourself.
Yeah there's some grey area there I guess. But it took me quite a while as a student to understand that I needed to cite sources even if I was "using my own words" and not quoting passages verbatim.
Certainly there are styles and broad arcs that many creations follow that are not directly attributable to a specific source.
