The price difference included the staffing costs - including onsite sysadmins, a NOC, network engineers, systems administrators, DBAs, Facilities Planners, Inventory Tracking Staff, Circuit Managers, Project Managers - fully loaded.
What I meant by "And then they would have to hire smart operations people" is that that is both (a) challenging, (b) fraught with risk, (c) not something anybody at Netflix with a sufficient seniority was interested in doing.
It wasn't that those staff cost a lot of money, though at the time, Netflix was paying a bit more for infrastructure staff, it's just that nobody was interested in building an operations empire. If they'd had a Chief Infrastructure Officer who had a passion for doing it, Netflix would have paid approximately 20% less for their infrastructure costs. But, at the end of the day, given they didn't have that CInfO, and 20% less on infrastructure wasn't that material to their business, they just outsourced it all to Amazon.