Japan doesn't even composite their movies at 2K even in modern day, though. Only Ghibli does it that high afaik.Yes, but it could have been done at a higher resolution than 2K. Entirely digital animation at 4K is as old as Toy Story. It's only live-action digital film that had a reason for going through the 2K stage - that being that the camera technology wasn't developed enough yet for 4K.
(sidenote: Innocence is sort-of a Ghibli movie)