At some point, I programmed a little 2D gravity simulation. So, I even had one less dimension in which objects could fly past one another, and I was still surprised how rarely they actually collide, despite literally being attracted to each other.

But the thing is, they generally get pulled by more than one gravity well or have previous momentum, so they rarely approach each other head-on. And if you’ve got a near-miss, that means all the speed they built up approaching each other is now slingshotting them far away from each other.