Podcasts, music, signal, and noise

I was unable to listen to podcasts on my morning commute. I have an older (2006) vehicle so I need to use an aux cord to plug phone into car to play over the speakers. It's likely that the aux cord is a victim of the Minnesota winter. Freezing and thawing temps are not helpful for cheap product electronic products. 

Instead, I listened to the radio - music - ahh. While driving a thought occurred to me. Perhaps humans did not evolve to have constant chattering in their ears - especially informative chatter.  It seems logical to me that brain is always alert and listening for signals. My new theory is that it’s stressful (and therefore exhausting) for one’s brain to constantly be sorting through noise looking for a valuable signal.  In the wild, we mostly heard wind, trees, and sounds of our little band of hunter gatherers - the noise of normal existence. When we heard a signal - dangerous animal, thunder, earthquake, voices we didn’t recognize (possible enemies) we sprang into action.  Listening to educational podcasts - not so mention political podcasts - produces a lot of noise as well as valuable signals - but I wonder if the optimal situation for processing danger signals is only a few times a day or week - not every waking hour of the day?