Many RFPs with an IT component require that the government own the code. This means a "build it" approach for ALL of these vs. buy it.
Ok, Healthcare.gov has been discussed endlessly but this is still a good example. There was zero reason to build from ground up other than that I assume the procurement required ownership. Many modules could have been purchased from other vendors for this and MANY other procurements.
I'm not referring to GSA schedules, which don't have this requirement in many instances. Build it ensures that the mega consulting firms waste govt resources either starting from scratch...or at least charging as if they do and changing code sufficiently to enable govt to own but not violate other IP agreements when they do reuse code.
In sum, let us develop custom software for some of this that we license to govt, and others, no different than Microsoft Word, Excel, etc.