Cavemen could tell the difference between feast and famine and so can we. It doesn't mean we can control ourselves. I don't believe the crux of the problem is related to the information on the nutrition label, or how accurately we read it.

My theory is counting calories offers a convenient apparatus with which to perform some mental gymnastics when rationalizing why one is not actually eating too much when deep down one knows they eating too much.

All the emotional reasons for eating too much are messy and we would rather not deal with them. The connection between mood and gut can be quite strong, and can vary wildly from one person to another.