Mixing Practices

I’ve been noticing a lot of mixes are overall panned a little to the left. My theory is that it’s to avoid making it sound fully “mono”. So it dosen’t feel like the audio is coming from the center all the time to give elements a little more clarity. But was wondering if there are any other reasons. If so I would love an explanation. Also just curious, why this right dosen’t work as well when we pan the majority of the mix a little to the right.