I'll make you this question OP: did you ever seen animated foreign/independent films not made by Disney/Dreamworks/Blue Sky studios etc. Because I'm pretty these folks don't have Disney budgets for their films, but the realizators really care to take animation as a medium to try to tell a story and not as a way to promote toys or product placement aimed to kids.
The fact in the West there still exist the stigma of "cartoons are only for kids" doesn't really help to establish animation as a medium of storytelling, a medium to tell any kind of story. Yeah there's animation for adults in the likes of adult swim and shows like South Park, but most of the time is for comedy effects (ofc there are exceptions like Bojack but are really far and in between). Anime also has proven that if they want it they can tell stories "not suitable for kids", and that something you have to respect the Japanese, anime has a plethora of subgenres: from your standard modern isekai trash to the weirdly artistry experimental films from the 70's/80's.
I does not help Disney has an absolutely monopoly in this regard, sure the majority of their films are gorgeous, have lots memorable characters, good songs and iconic moments in the history of the medium, that establish Disney/Pixar as one of the most important companies, so much that now are owners of 75%/80% of all the entertainment media (at least in the US). So success like that made us believe that if you want to success in the animation industry you'd force to make adaptations of children's stories, add some songs here and there, make sure your film is whimsical and magic and Profit! your film is eligible to win one of the most predictable Oscar categories. I like Disney but you'll never see them making an animated documentary about a soldier with PSTD or a film about autism, depression and suicide thoughts.