Eliminate DARPA? The majority of what they fund is really cool, useful technology that just happens to be a little too risky or costly for businesses to fund (especially with capital harder to come by today). Look over their list of projects; you'll find a shortage of "ultimately useless death machines" and an abundance of worthwhile science and engineering. I doubt you could have made a convincing business case for building the ARPANet -- too expensive, and how are you going to earn money from it? -- but it turned out to have been worth doing anyway. Likewise for most of the DARPA projects I've been seeing.