> You get better at modeling the trajectory because the neurons physically move closer together as you learn
I think "modeling the trajectory" is not necessarily what we are doing either. It's more likely we are using much simpler heuristics. If you are trying to catch a ball flying through the air, you can just look at the ball and modulate your running speed to keep your eyes at a fixed angle until you catch the ball. It's much more analogous to a PID controller than a model of the trajectory.
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The brain doesn't process vision anywhere near fast enough for some of the stuff you see in fast sporting actions if it were purely reactive - batting in baseball/cricket, returning a table-tennis shot, etc. In some cases the time available for movement is extremely restricted and yet people can respond accurately. We may not know exactly how the brain implements it, but it clearly uses prediction to estimate where the object is going to be - i.e. it is, in some sense, modelling its trajectory.