Anime Films, good looking ones at least can be re-mastered to 4k if it's given to a good digital company. TV anime have to have insane quality to hold up well if scaled up, probably something from Bones or KyoAni.
I'd give it 5 years for anime movies to be in 4k native, but I'm still not sure since Japan's business practices with respect to anime are pretty asinine. After all they ask people to buy 4-5 Blu-Ray discs for 13 episode anime, which is idiotic as hell. And that comes to around 100$(This is only in Japan).
Also since a lot of anime these days are in CG and they look really ugly(except a few, like Land of the Lustrous), it'd look like turd in 4k.