[dogma1138]

Impacts of this size don’t leave enough evidence for you to know where to look, especially after 1000’s of years of man caused and natural erosion.

An air burst impact that’s large enough to take out a city won’t leave a major impact crater. And back in the day it might even be the case of the perceived cause contributing more to the decline of a city or even an empire than the physical damage.

If a meteor hit blows up your town when you have no ability to comprehend what just happened other than god/gods are angry you gonna move to a less cursed place.

It can also cause social impacts such as the toppling of a given religious or leadership class because they angered the gods.

[koheripbal]

OP's analysis demonstrates that it's very possible to detect theses events 1000s of years later, if you examine areas near the explosion.

[gota]

Yes, but they are testing the area because we know a settlement there was destroyed. We'd have to test random uninhabited (or at least currently uninhabited) areas for which there are no indications of anything special to get a better picture

And not even that guarantees a complete picture - what if a tsunami event erases or conceals the record of something like this? Volcanic activity? Desertification?

My point is that we can't reason about the rarity or uniqueness of these events as a main factor for accepting or refuting the hypothesis