Probably because that is not the meaning of the word deliverables (as noted in a prior post).
Deliverables indicate various efforts or objects that can be “delivered.” In installing a computer system, depending on the venue, this could include the actual server on which it will operate, the installed software, manuals to be distributed to various users and support personnel, passwords, and the training to continue using the system once the project has been turned over. If the customer already owns the hardware, the hardware is no longer a deliverable. If the customer refuses to pay for training, training is not a deliverable.
For the installation of a water line, the deliverables can include the actual pipe and fittings, installed, the testing of the lines to establish that there are no leaks, the prints of the original designs, the “as built” corrections that identify where the pipe was really installed, regardless where the design print claimed it would be, the chlorination of the line with a report by the water department that the bacteria count in the new line has been reduced to a sufficiently low level, and the restoration of disturbed property to a condition acceptable by the property owners. No money is paid to the contractor until each of these disparate collections of reports, documents, physical objects, and labor have been completed. This is not simply a list of tasks. The task of preparing the design print and the “as built” print is immaterial until the appropriate governing bodies have received the physical print (or, more typically, computer image, either on disk or by e-mail or ftp). (Yes, you can call the delivery a task, but it is confusing when discussing what has been delivered if you are looking for an object and someone keeps referring to the work to deliver the object.)
Deliverable is a handy, single word that provides a list of everything (physical or not) that must be delivered for the project to be completed.
This is not to say that the word is not abused, and I have no problem with excoriating people who are misusing words or turning valid terms into meaningless buzzwords, but often the actual words have legitimate meanings.
