This discussion is an example of a philosophy of sizing AC power components (transformers, power cords, house wiring, etc.) so as to provide the peak power requirement, which, as we all know, far exceeds the average. This is necessary because there is no device (other than the spinning momentum of an alternator) that can store AC power.
However, almost all the AC is used to generate DC power, and there are devices, capacitors, that store DC. At one time a popular Mod to audio power amplifiers was a bank of outboard capacitors. It seems to me that this is a better, and less costly, way to provide greater reserve power.