>So they're interrupted more frequently that the time it takes to refocus and therefore never complete any task?
No, they just never complete any task while FOCUSED.
They still complete tasks, but distracted, and thus in a sub-par and slower way.
Sounds about right to me. /s
More seriously though, that "every 11 minutes" figure is most likely an average, so there will be intervals much longer than that.
So they're interrupted more frequently that the time it takes to refocus and therefore never complete any task?