Well, it turns out that the amount of sleep a person needs is genetically controlled. At the moment, only 3% of the population seems to have the gene that allows them to thrive on 5-6 hours of sleep a day. So far, genetic engineering has been focused on improving food crops and curing certain rare debilitating diseases. That's all fine and good, but to have a bigger impact, we should start finding a way to genetically engineer our next generation of workers to require less sleep. With the huge economic benefit of a workforce which sleeps less and works more, we should be devoting a lot more resources engineering a more wakeful workforce.
Until that breakthrough happens though, the PHB can still induce caffeinated productivity in his employees and try screening for the non-sleepers during hiring.