> any one of them taking out a couple sats and causing debris would cause a chain reaction that would effectively turn space into a dump

You may not realize how big space is relative to the size of a few sats.

https://conference.sdo.esoc.esa.int/proceedings/sdc9/paper/3...

You may want to read an actual study about it. And this doesn't even consider the possibility that militarization of starlink satellites may cause them to get taken out, which will trigger the KS the same way.