That assumes that consistency between viewpoints is actually desirable - part of the charm of 2D animation is that things can be stylized or exaggerated or simp

That assumes that consistency between viewpoints is actually desirable - part of the charm of 2D animation is that things can be stylized or exaggerated or simplified in ways that don't come naturally in a 3D workflow, where the "default" is for things to fit together realistically and any deviation from that takes additional effort. If you do want numerous 2D artworks which share a realistically defined 3D space then that can easily be done by making a very rough 3D scene and then painting over it, you don't need any AI for that.