The anime community has, for as long as I've been a part of it (13 years or so), decided that anime is "animation made in Japan". This heuristic has actually worked pretty well.
But the lines are increasingly blurred.
- Japanese produced shows are outsourcing some animation to China and Korea, and sometimes taking direct funding and story writing input from the USA.
- Non-Japan produced shows are taking notes on what works, drawing on it for inspiration, and in rare recent cases even outsourcing animation directly to Japan.
- There is a TON of money in gacha games, and the biggest "anime" titles some people may recognize are gacha games, butand the majority of those are run 100% by Chinese companies. Ironically, sometimes sending them over to Japan for the TV adaptation.
Just like food: Italy may have "invented" pizza, but New York pizza is now its own thing.
On the higher quality end of the spectrum, I think one of the main differentiators is just how seriously the staff takes the production. They lean into the cinematography, storyboarding, directing, music, choreography, etc just as much or more as one might expect from western live action prestige TV. This is exceedingly rare in TV animation in the US and is only really seen in our animated movies (which are rare these days, at least in 2D form).
The other thing is that high quality anime is exceedingly good at building atmosphere and creating vibes. Half of the enjoyment of Cowboy Bebop for example is just basking in the ambience.
To be fair, most Japanese anime is also meant for kids and teens, but they were willing to explore content that would absolutely shock Western parents (violence, sex, nudity, as well as more nuanced stuff like sociopolitical commentary).
Is this different today? I feel modern Japanese anime is more toned down compared to say, the 1990s, while non-Japanese animation has been “toned up” in content.
Rather than "if", here's two instances of that idea I know of:
https://en.wikipedia.org/wiki/Suicide_Squad_Isekai
https://en.wikipedia.org/wiki/Marvel_Anime
Edit: And it actually looks like some anime studios did get in on Star Wars: https://en.wikipedia.org/wiki/Star_Wars:_Visions
Are you unaware of https://en.m.wikipedia.org/wiki/Star_Wars:_Visions
??
Avatar, Star Wars, even Boondocks comes up.
I think My Adventures with Superman was Korean at least, but stylistically it's close to anime.
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The one people may have forgotten about is RWBY, which was the famous Texas Anime (erm... Texas made anime-inspired art?) that split so many people with debates on 'Anime or Not'.
I would definitely think that all the French-Japanese and Italo-Japanese coproductions of the 80s somehow qualify as western anime, yes. See for exemple Ulysses 31 and Esteban: Child of the Sun.
Then you have things like Radiant which a “manga” by a French artist in French which was turned into an anime by a Japanese studio.
I guess there probably is animation made in the typically Japanese somewhere. I can’t really help you there because I only read mangas and never watch adaptations (they are always strictly inferior to the material they adapt). So the only Japanese/Korean animation I watch is original content of which there is sadly very little.
There's not really anything stopping creative individuals who aren't Japanese from producing anime. The thing that many attempts miss (and I suspect what makes hardcores bristle) is that they tend to miss the point in one way or another, resulting in a product that might have many of the outward characteristics but ultimately misses the mark.
In my opinion Avatar is actually pretty close. I've seen clips from various animated productions from France that also seem to capture a similar spirit.
Similarly: One Piece / Luffys gears have been confirmed to be various powers that Tom and Jerry (the cartoon cat and mouse) have done over the decades with Gear 5 being a full on cartoon logic power up.
The amount of play and borrowing from Japan to America and back to Japan and back to America is epic.
Samurai films are inspired by Westerns. But then Star Wars was inspired by Samurai films.
Bouncing back and forth between the two cultures is part of the fun of it all. Including borrowing words like anime, Isekai. Or Japan borrowing the letter 'H' (ecchi) from us with completely new meanings.
Can you have "Western" anime? Some hardcore otakus scoff at the idea. If you made an animated version of Star Wars - is that anime? Is Avatar: The Last Airbender an anime?
"Chinese anime" or "Korean anime"? Again, some would scoff at the idea. But what is all that Hoyoverse stuff? Or all those Korean webtoons (though that's really more comparable with manga - and the korean word "manhwa" uses the exact same Chinese characters as "manga").