It's actually mostly because we allow objects to fly too high. Small height differences have a huge difference in orbital lifetime (and therefore risk). https:

It's actually mostly because we allow objects to fly too high. Small height differences have a huge difference in orbital lifetime (and therefore risk). https://commons.wikimedia.org/wiki/File:Orbital_Debris_Lifetime_Diagram_Low_Eccentricity.png https://commons.wikimedia.org/wiki/File:Orbital_Debris_Lifet...