"Chicxulub impact" seems to be functioning as a bit of hyperbole to imply that this collusion was absolutely devastating, by analogy to the K-T extinction event 66 million years ago.

Not that I really can tell what this was devastating to. Maybe United States v. Apple (2012), where Hachette Book Group, Inc., HarperCollins publishers, Macmillan publishers, Penguin Group, Inc., and Simon & Schuster, Inc. conspired with Apple to raise ebook prices?

I can't say for sure, but is it possible they're referring to the founding of the Internet Association in 2012?[0]

I don't think it's that, because the Wikipedia article makes it seem like it was a force for good, but at the time, it wasn't certain at all that it would be that way.[1]

Beyond that, I'm not exactly sure what might be meant.

[0] https://en.wikipedia.org/wiki/Internet_Association

[1] https://reddit.com/r/technology/comments/xs4qw/google_facebo...