I think something people forget is that the candidates are standing like 10 feet apart. So with Trump’s mic muted, we may not be able to hear him, but Harris probably still can.
I think that’s one reason Biden seemed so feeble in their debate—he was having trouble focusing on what he was trying to say with Trump rambling on in the background. With the mics muted and the camera focused entirely on Biden, that was totally unapparent to the viewer and it seemed like Biden was just losing his train of thought for no reason. I’m sure Biden told Harris as much, which is why the Harris campaign was pushing for unmuted mics.
Actually, there’s a lot of evidence that points to intelligence being a sexually selected trait rather than naturally selected, so in that sense it may actually negatively correlate with survival. In other words, your big brain is the human equivalent of peacock features; it will get you laid but doesn’t do much good when a tiger comes around.
Think of it this way: to sit around doing math problems all day, you have to have the basic necessities for survival dealt with, which shows you’re a good mate within the current environment. Which is all well and good until times change, the going gets tough, and you need to kill something to put food on the table.