I am not the best to answer this but I wonder a few things that may help or make more questions.
Why can't fruit and the occasional tubular (like sweet potatoes) not provide the necessary carbs.
I understand that certain training requires the user to utilize glycogen as a fuel source BUT shouldn't the limitation of muscle glycogen only be limiting if one is doing repeated or long duration anaerobic activity?
It is sad that the measuring stick of our progress is the speed by which we distance ourselves from the natural world. Even sadder is that we will only see this when there is no nature left to save.