It could be that life at our current level is more observable to life at our current level than more advanced life would be. The "Dark Forest" hypothesis from 三

It could be that life at our current level is more observable to life at our current level than more advanced life would be. The "Dark Forest" hypothesis from 三体 would be one explanation, but even that isn't required. It could be that advanced life can better meet its needs via technology that we can't sense. That was certainly plausible before we could broadcast over the electromagnetic field, which wasn't so long ago. Perhaps it is still plausible, because we're still missing out on something important.