>But modeling and animating 10M polygons requires a Hollywood movie budget, while I can model and convincingly animate 1K polygons myself.

I can make 10M polygons just by opening blender and asking for a UV sphere with a bunch of sides... Artists using the sculpt tool can produce models with humongous numbers of polygons, and then they have to work really hard to optimize them. I would argue the exact opposite of your claim. Models with more polygons are easier to end up with than models with fewer.