Unfortunately it's the wrong comparison to make. Two cars sitting still in a car park won't collide with each other, but there's no way to sit still in orbit.

Unfortunately it's the wrong comparison to make. Two cars sitting still in a car park won't collide with each other, but there's no way to sit still in orbit. Any two circular orbits at the same altitude will intersect at two points. You have to be very careful to make sure objects in such orbits will not collide with each other. It's far easier to make the orbits slightly different sizes or shapes, so that they don't intersect at all. In any case, the need to be in an orbit to stay in orbit severely restricts your free choices for where to put your objects, so there is not as much free space as you might expect.