Don't look at the surface, look at the sky. You hardly ever see another airplane except occasionally when near an airport.
And yet, mid-air collisions do happen, despite the systems in place to prevent them.
The fact that all of this stuff is moving makes it a completely different proposition. The fact that a collision just makes more junk to go out and collide with other stuff results in a potentially disastrous feedback loop.
Also, very few things up there are made to be durable in the face of collisions. That adds weight for, until recently, no apparent value. So even small pieces of debris are very dangerous to useful equipment.
And yet, mid-air collisions do happen, despite the systems in place to prevent them.
The fact that all of this stuff is moving makes it a completely different proposition. The fact that a collision just makes more junk to go out and collide with other stuff results in a potentially disastrous feedback loop.