That's what billions of years can do.
Statistically speaking the likelihood of us finding alien life even if we search is cataclysmically low. We live in the equivalent of a pocket of antarctic ice compared to the rest of the galaxy, so we would be hard for aliens to find, the milky way is in an intergalactic void.
Not to mention with the explosively exponential progress that would come with an AI singularity a species could theoretically undergo billions of years of growth and evolution in the span of a few seconds, there's no telling what kind of goals an organism that advanced would have, but it's possible that they wouldn't choose conquest, or they would ascend to higher dimensional planes instead.