[kroltan]

For (the vast majority of) games the player can be looking at anything on screen, not just a specific point.

In real life, eyes track objects in order to minimise blur.

But realtime motion-blur implementations just blur everything that moves relative to the camera, which is not correct, and makes the human looking at the screen lose track of the objects they were looking at.

If we had pervasive perfect low latency eye tracking then a game could pull off something that actually looks plausible, but that is not the case, so the only games that can get away with it are the ones that are largely a movie and can take advantage of the motion blur cinematographically.