Yeah, let’s not forget how convincing all the faked evidence for the SSBUltimate “Grinch leak” was. Alot of people have too much time on their hands.
Nintendo wouldn’t even let Archie Comics use any of their properties, (despite how well their Sonic & Megaman comics were doing at the time) and they turn down offers for new cartoons/movies like crazy. Nintendo is notoriously stingy with their properties. (They’ll allow Mario to be on a can of SpaghettiOs, but not in a new cartoon/anime, or anything.)
And I’ll be surprised if that Super Mario animated movie that was announced years back, ever gets started.
There was also a Metroid movie in development hell back in the GameCube era, but Nintendo cancelled it.
PS: Pokémon is a different entity from Nintendo, so they’re less stingy.