This whole modern approach is also seriously undermining just how important fanfiction is - from a historical standpoint.
The concept of fanfiction formed and forged the earliest stages of literature in Europe. Because the majority of authors in France, Germany and Great Britain looked at that funky little Celtic dude Arthur and thought “hey, he’s neat. I wanna write about him”.
The entire concept of a book outside of religious purposes was born out of fanfiction in my country.
There is no “first canon” for Arthur where he came as the prince of Camelot, with his sidekicks Lancelot and Merlin and his endgame love interest Gwen.
Arthur was some random hunter when he started out.
Someone’s fanfiction made him a prince.
Someone else’s fanfiction gave him a round table.
Someone else’s fanfiction gave him Merlin at his side.
Someone else’s fanfiction gave him Morgana, gave him Gwen, gave him his swords.
And, to this day, we still write Arthurian fanfiction. Literally last year there was a movie adaptation that is, by all intends and purposes, fanfiction, because it wasn’t even close to a literal adaptation of the source material (The Kid Who Would Be King). Heck, BBC’s Merlin, itself an Arthurian fanfiction, remains one of the biggest fandoms that people today write for on AO3.
You were a joke in the middle ages if you tried to write your own stuff. Who’s interested in your stuff? You were only a respected author if you wrote fanfiction. The most famous medieval German authors are famous because they wrote fanfiction about some knightly OCs they created who served on Arthur’s court. That is the literary legacy of the middle ages. Arthurian fanfiction.
Yet somewhere along the way, this concept of “I find x story/element cool and want to elaborate on it more, shift the focus onto an aspect of this original source material” has gotten this “eh, it’s fanfiction” connotation and lost respect.
Even though this very concept is still being used - even outside of the actual medium of fanfiction - and it is still being used for the very same purpose it was used for in medieval times. Original movies often don’t get as much recognition as adaptations of existing source material that the audience is familiar with. People see a movie about a character they’re familiar with and seem more inclined to buy a ticket to see the 10th new interpretation of Batman or Superman or Snow White. How are these new interpretations of familiar source material that usually add to the lore, reinterpret characterizations and dynamics, any different from fanfiction?
But heaven forbid we call The Dark Knight Nolan’s Batman fanfiction. No, fanfiction is that silly thing that we can’t take seriously, but that new Joker movie, that however is high-end art.