Well… just for that one employee, break-even is about three such per hour – with no slack periods (or fees to airport/airlines/whatever). For a company with overheads of storage facilities package handlers etc., perhaps five or six per hour. At some airports, this target may be reached easily, but at most perhaps not.

As to why deleivery took so long, that too may depend upon volume. I recently made two cross-country small purchases (a USB drive and a fan). One arrived in four days, one took over two weeks – because the delivery company waited until the originating companies had enough to justify sending out a truck for pickup, and the two companies had large differences in volume/weight.