This is like asking a dodo in 1598 to be able to explain what the threat of humans are. Their inability to do so isn't related to the probability that the threat is real.

Likewise, our inability to articulate the threat posed by AI isn't evidence that a threat does not exist. We simply don't know that threat is and even if we knew there was a threat, there's no guarantee that we would be able to comprehend it enough to describe it. Rather, our inability to comprehend super-intellegent threats make us more susceptible to identifying and stopping them.

Why don't we apply the same logic to the status quo? Because we are, for the most part, exposed to shocks and change within the regime of normal variance and have continued to exist which is evidence for continued existence. Planetary co-habitation with super-intelligence represents a many-times-beyond the standard variance of shocks to our natural order.

If any of the lifeforms we've extincted already were as intelligent as humans, would that have increased their chances of survival? Personally, I see that as an easy yes which implies that differences in intelligence are at least somewhat correlated with extinction outcomes. But perhaps others see it otherwise.