It looks like this has been an unpopular suggestion, but I wouldn't discount motivation completely. A lot of early 20th century economists thought centrally planned economies were a great idea, based on the evidence of how productive various centrally planned war economies had been. Presumably there's some explanation for why central planning works better (or doesn't fail as badly) with war economies compared with peacetime economies, and I've always suspected that people's motivation to help the country in wartime was probably one of the factors.