I sometimes wonder if "like humans" is the key. What if past some level of technical advancement, organisms cease inhabiting the same scale as us. Physically and temporaly; they become microscopic and perceive+act on a time scale faster than us by orders of magnitude. Why inhabit the days/hours/seconds timescale when you can have the same experiences in micro/nanoseconds? So we would be mostly not interesting to them and expensive to interact with at our timescale. Not sure if we would notice them right under our noses.