Seems cherry picking to be honest.
I loved The Maxx and Aeon Flux as a kid, but that being said equally mature themes can be found in Adventure Time. If anything, the fact that shows like Adventure Time and so much of modern animation now can tap into a multiple of age ranges suggests a deepening complexity and relationship to consumed media.
The Maxx, whether in its original media form or its adaptation to the screen was definitely not for kids. It had incredibly dark scenes and it relied on that dark, veiled storytelling to communicate the ideaof this loss of identity and self under the crushing reality of poverty and social stigma and the battles we create for ourselves in day-to-day life.
And shows like Adventure Time can tell equally bleak, equally dark themes of varying accessibility whether young or old viewers is a sign of that evolving idea of narrative. It's not as hamfistedly dark ... which is kind of a problem I find with concepts of Grimdark garbage lore and worldbuilding that you get with things like 40K. A videogame like Papers, Please is fair more terrifying and soul crushing without (too much) blood or open violence simply because we can see it happening now ... it reminds us that as a society we're either living it as individuals, or about 1 or 2 steps away from living if we have the privilege to be without it now ...
All without high fantasy elements like daemons and space elves.
My Little Pony with a single song and reprise tells a truly heartwrenching tale of the realities of the alienation of one person's work through systems of capitalist production and what you might have to potentially sacrifice if you want to save some of your soul in the process. How it destroys not only the worker, but inspiration and artistry on its own ... and yet somehow Hasbro didn't pull the plug. All packaged in a bright, colourful, somewhat comedic and catchy fashion ... right up until you recognize what the moment is trying to imply. And that one song probably has saved you an hour interpreting Entfremdung theory by giving you a direct (if fanciful) example.
Also subliminal condition for the young'un to join with whatever incarnation of the CNT for true proletariat friendship ...
I digress ... frankly if yu rely on blood and death to tell an impactfully bleak or heroic tale of the human condition striving to see itself through its agency and the struggle for one's own self-building, you're probably not a good storyteller.
That's not to say you can't have blood and gore and death if you enjoy those themes, but that's solidly worldbuilding ... not a question as to its emotional weight or impact, or its intellectual designs.
'Adult' shouldn't be shorthand for bloody or vicious... because frankly something like the Dynasty Warriors series is lighthearted and that has you murderizing thousands of people. Sorry ... 'K.O.ing' thousands of people willy nilly with massive weapons no human could conceivably wield well. To put it bluntly ... a game like Dark Souls tells a pretty bleak story regardless of your character's agency. I would argue it doesn't tell a very good story ... in fact the only decent storied (not merely lore, not merely character vignettes, actual overbranching story) Dark Souls game was DS2...
But the story wasn't more bleak or more adult by carrying the biggest murder-death weapon in the game ... in fact some of the weapons were downright fucking ridiculous and looked ridiculous.
Same thing with something like The Picture of Dorian Gray. Infinitely a far more bleak depiction of the world simply for Dorian's (and Lord Henry's) presence, that as if their machinations, their obsessions, their wastrel lives and their pointless pursuits both vain and in hopeless salvation without recognising there is nothng of worth to them is a bleaker story of examining of many different types of personal suffering one might not even live to endure.
And honestly, you could make a PG-13 movie of that just simply by accurately portraying the book. Like one definite murder and two suicides, which you could still hold true to the book and its sentiments by not directly showing. Yet I challenge anyone to find a bleaker attitude to the human condition than that tale.
Barring Catch-22 that is ... but nothing is as good as Catch-22. Also how fucking mindnumbing it must of been given the author actually lived that madness of conflict. How he statistically shouldn't have survived WW2, statistically been killed three times over, given the number of hours in the air, the number of missions, the number of direct engagements with enemy air defenses and intercepts.
That movie you couldn't do PG-13 ... but so much of the book wore lightheartedness that was in truth incredibly bleak and soul-crushing. Like Major Major Major. How he got his name, why his father chose it, and because of that absurd humour becoming a self-fulfilling prophecy via a filing error that simply recorded and maintains both position and namesake as Maj. Major Major in the U.S. Army Air Forces. Displaying no less the same mechanical and thoughtless humour as his father to the detriment of all...
Movie is bad (well, it's actually pretty good .. just in comparison to the book which is pretty unfair a bar), but it get some of the sentiments right. And arguably you could never properly transform it into a movie in the first place.
