The blast radius from a maritime collission is (mostly) relegated to the vehicles in question [1]. The same is not true for satellite collisions.
[1] There are counterexamples, like in narrow chokes & whatnot.
[1] There are counterexamples, like in narrow chokes & whatnot.
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.
You can remove curbs and any other barrier to simulate the fact that cars can maneuver away from a crash site, but if no site is ever cleaned, and no car has meaningful brakes, crash sites are much scarier.