Science

If AI is so self-amplifying and self-improving that it exterminates its creators or otherwise stymies them, then it would be smart enough to expand Borg-like in the galaxy. It does not seem to have done so.

So the absence of evidence is indicative of other things, like the dominance of physical impediments and the extreme time scales involved.

Speculation about civilizations being thwarted by AI is pure speculation. No evidence, not even indications. It's conceivable but entirely speculative at this point.