Not really though as the risk is still per satellite. They have a greater chance of an individual loss but their individual risk per satellite is the same (or maybe higher because the collision could be with another starlink).
So it seems like the 1:10k vs 1:100k threshold would be a function of the cost of a loss from a particular incident rather than the risk of a single incident among the 4k satellites.
Thinking from an insurance standpoint, the cost to insure probably depends on the number of satellites overall and total potential loss, not just insuring for a single loss.
Yes, but when it fails for whatever reason you want it to stay in one piece and just naturally deorbit within ~5 years due to drag. A collision is likely to create more fragments, that in turn have a chance of hitting your other satellites, which would create even more fragments. You don't want that to happen too frequently.
There's enough atmosphere in those low orbits that chain reactions aren't a huge concern for the rest of human spaceflight, but they are a concern for keeping the Starlink constellation alive.
So it seems like the 1:10k vs 1:100k threshold would be a function of the cost of a loss from a particular incident rather than the risk of a single incident among the 4k satellites.
Thinking from an insurance standpoint, the cost to insure probably depends on the number of satellites overall and total potential loss, not just insuring for a single loss.