Snoring is probably an overall detrimental trait, given that it’s primarily due to our our upright anatomical changes since it comes with poorer breathing - it’s just not been detrimental enough to outweigh the other benefits of our evolution though. Plus, our tendency as a communal species to stick together in groups likely outweighed any effect (positive or negative) in the “predators eating us in our sleep” category of natural selection.

I’m no expert, that’s just my hunch. But this is a good question IMO!