> same is not true for satellite collisions

Space is big. Volume grows with radius in a way our intutiions don't seem to intuitively understand. Yes, debris in a space collision go further. But they're still bound by their energies. And that larger volume of collision debris (plus all other stuff in orbit minus the Moon) is still a smaller fraction of the orbital space than e.g. commercial air space on earth, and yes, that's including oceans.