It is not quite as rare. I calculated it to be less common than being hit by a meteorite, and added a section about that and the Birthday Paradox to Wikipedia, to the article about UUIDs. It got removed / replaced a few years ago however. (If my source was correct, there was actually a woman hit by a meteorite, but she survived, with a leg injury.)

If you do have a UUID collision, chances are extremely high that it's either a software bug, or glitch in the computer. It could be a cosmic ray. Cosmic rays messing with the computer memory or CPU are actually relatively common.

About as rare as an asteroid typing an ellipsis and clicking the add comment button.

Well it would be statistically even rarer for that UUID collision to happen and the earth to be destroyed by an asteroid.

It's very common if you improperly seed, as others in the thread brought up! Or in your framing, as rare as earth getting hit if it were surrounded by a sci-fi density asteroid field.

For a single database using UUIDs, yes, it's astronomically rare. But it's quite a different thing to say that no computer system on Earth has ever experienced a UUID collision. The number of systems out there is also astronomical.