In kinetic warfare we understand force projection, and the human muscle became the horse muscle became the machine muscle. My sense of information/psychological warfare is that it is "focus projection". The constraint is different, and the nature of endurance changes.

My weariness is of a different kind to, say, getting off a Scottish mountain in fading light. Pressing on and making myself focus more takes away too much from the next period. I am having to match demand to a degraded supply, because focus power isn't like muscle power.

The category difference is muscle power is work and you can gain more, whereas focus is something you lose, like silence being overtaken with noise. You start with perfect focus and task persistence, and then it degrades. Whole books will be written on this some day.