> It can be a lot easier to model, rig and animate a 3D

Some do. The talking heads in Fallout were sculptures, for example (I think from paper, but cannot remember well).

But drawing vs rendering from 3D models can be either an aesthetic choice (Braid is an example) or an optimal choice depending on your workflow, expertise, equipment etc.

And in the current times, also Generative NNs I think were proven a possibility to generate animation.

> in the current games economy

Indie vs mainstream have different ways.