We are already in some sense past the threshold of sats required for a potential civlizational collapse that would be caused by the loss of access to space.

There are way too many sattelites, starlink militarizing means it's a viable target now for enemy nations, 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, let's not even mention that military = more money = more sats, making it even riskier.

Or the fact that at any moment those sats could also die from a carrington+ level event.

> 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.

...there was civilization long before satellites.

The relative impact of Kessler syndrome is honestly overblown: we're simply not that dependent on satellites for day to day activities. It would be an economic disaster, but those aren't civilization ending.