Government IT has been characterized by long term monolithic systems that fail to deliver. Part of the problem is approaching IT as a complex durable good, like a battleship, with complete specifications, known life-cycles, and defined missions. Fighter aircraft have six generations of evolving technology and missions, each having known maintenance cycles, life spans, and changing requirements based on future planning and doctrine, as well as, mission feedback.
IT has none of that because it has no duty cycle or doctrine. IT can be obsolete on delivery, regardless of development timeframe. IT delivery can redefine all previous requirements. IT has very little longevity, even if successful on delivery.