You could be right about premature optimisation. Shift workers live shorter lives than colleagues doing the same job. So, if you increase waking hours now then you may not increase your total and you might not spend them most productively.

Regarding greatness, political office impinges greatly on sleep. Margaret Thatcher was widely known to get as little as four hours sleep on a regular basis. Successive British Prime Ministers age relatively quickly after obtaining office. Unfortunately, I couldn't find any other examples. Therefore, it is likely that examples are outnumbered by counter-examples.