> especially with all the stuff that SpaceX has put into orbit in recent years

I've heard this repeated a lot but I've never seen anyone do the maths. StarLink satellites are all in very low orbits, so intuitively it seems like most debris from a collision would just end up deorbiting.

90% of starlink satellites are >400km in altitude. They aren't in very low earth orbits where that intuition even might be correct. They're above the space station.

I've definitely seen math done - though I'd have to dig it up again. I think in FAA filings.