For a couple of reasons-
This is a custom-built software system only used by the government. It will never be used commercially, nor will any modifications to it, make it available for commercial use. Even though there is a listing of labor cats for the positions, there is no "commercial" knowledge of the systems... For example, if the government needs a bathroom built in a faciltiy, that knowledge is commercially known and can be done (one would hope quickly), versus the government asking a vendor to develop, modernize and enhance a system they have never seen, touched or ever worked on... industry wouldn't be clamoring for technical information... plus with software development the requirement is very fluid in terms of week to week needs and changes... hope this further clarifies my position...