Meyer does a good job of not only detailing the difference, but pointing out the consequences of these missed opportunities:
The lack of appointed leaders can create problems. Too many vacancies can put agencies “in stand-down, waiting for policymakers to show up,” said Terry Sullivan, a political science professor at the University of North Carolina who has studied appointments.Meyer is absolutely correct that both Obama and the Senate are at fault. As far as what can be done, regular readers know my suggestions: more presidential attention to appointments; a lot less vetting from both the president and the Senate; and, as I argued again today, simple-majority cloture for executive branch nominations.
Acting heads of agencies “don’t make any big decisions,” said Cal Mackenzie, a professor of government at Colby College who has studied appointments since the 1970s. “Your authority is not going to be recognized in the same way a Senate-confirmed appointee is going to be recognized.”
The first step, however, is to identify the problem and to realize it's important and has important consequences. So: nice catch!