western cartoons are made for either children or enthusiasts. Occasionally there's something made for all the family or adults.
Japan has a dedicated demographic of Otaku, most of them grown men. They're looked down upon as weirdos, but they're substantial enough. So most anime is made for grown men or teenagers. Things made for grown men have broad appeal, though, especially if they're not gruesomely violent or sexual. There's plenty of demand for general audience animation, but studio execs in America aren't smart, they're traditional. It's all animated adult """comedies""" or kids shit.
I really do think America has more latent talent than Japan, but it isn't used. I don't think that talent is even in the industry itself, at this point.
Similar with comics, I think America has far more talented writers and artists, but they're either wasted on super heroes or they're not in because they don't make the kind of shitty comics the failing industry wants.