That doesn't really mesh with the "no productivity hit" arguments though. For all that knowledge workers resent the idea that being there at certain times has much impact on their output, in many vocations that's the plain and simple truth

> That doesn't really mesh with the "no productivity hit" arguments though

Sure it does. Any customers who call on Friday will quickly learn you are closed, in future they'll call mon-thurs instead. The no-productivity-hit claim is based on the fact that both businesses and customers are adaptable and quickly change their behavior to match new norms.

But the widget that would have been ordered, made, and delivered on Friday will now get delivered on Wednesday due to the backlog that built up

The widget's production and delivery has nothing to do with the receptionist, though.

Most likely the widget is being ordered online, and, since everyone knows the factory is closed on Friday, it'll be made and shipped on Monday, and delivered on Tuesday/ Wednesday, regardless of whether it was ordered Thursday or Friday.

If the factory has encountered a backlog, the mechanism for worker overtime or a 2nd shift still exists.

Or stay open seven days a week, with one day of overlap for two workers.

or decide that working week-end counts more that 3 days and there is no overlap needed.

You can rotate for the week-end shift too.