>>151184892
That's a two fold issue.
One: American animated and comic media never tried to go for a mature audience and when it did, it was never handled maturely or with an over sexualized, sometimes slapstick humor. The closest the US ever got was Ralph Bashki, and that was too vulgar at the time but it poked at America's race issues of the times. For comics, you had more variety, especially Alan Moore pushing boundaries, but the issue with comics in the US is they will never quite take remove the cultural yoke of being adjacent to capeshit slop and therefore childish. Meanwhile anime and manga is universally regarded even by plebian normies that it's more mature. But it's heavily cultural optics, and that the old comics industry is in the way of letting a new comics industry florusih. The only thing they've really tried is live action cape-shit and rebranding their old capeshit slop into rainbow cult capeshit.
Two: Because art has been degraded culturally extremely heavily. It was heavily seceded to the territory of the far-left, the main memes are that no one leaning right has ever been an artists, and if they were, they held no cultural footprint, and that you have to be gay, since some of the old classical masters were so the realm of art is in that camp now and forevermore. American's also have never really held art as a high point, despite artists like Rockafellar and J.C. Leyendecker and instead Andy Warhol being held up as the examples. Hell, the American writers that shaped much of fantasy are usually the laughing stocks in modernity, Robert E. Howard (Conan) and Lovecraft.