Oh, aliens probably exist, but the likelihood they are intelligent enough for space travel is close to 0%. Just look at how long life on earth has evolved and how many species there already were, then realize only one species got intelligent enough to understand what space even is.
Life may even be abundant, but it doesn't need to be smart. We may be an anomaly within an anomaly.

Though we are screwed if we find evidence of even a single microbe as its evidence that we haven't survived the hypothetical Great Filter.