This is a reflection of a complaint I frequently make about so called "world models". It's more accurate to call them video game models. They don't simulate the world, they simulate video games. For that reason a common issue with them is that the physics are video game physics rather than real world physics.

I'm sure you're probably right about video games being used in training and, as a result, the models reflecting video game physics: No air resistance, no static/dynamic friction curve, etc.

However, I don't think that's the problem in the example of the marble bust not toppling. It would have toppled in a video game engine as well; they model gravity and inertia just fine.

I think what's happening is the model isn't being a world model at all, it's being a language model. It's trying to make the "scripted" thing happen, and it probably "feels" like the script should end in the bust on the pedestal.