The whole point of blue-sky R&D funding is that you can't plan exactly what you're going to get out of it. Today DARPA is a bit more focused on practical application than it used to be, but it's ethos is still: "let's throw $10-30 million at a bunch of smart people and see what happens." The "plan" is to fund fundamental R&D and hope something really useful comes out of it. In that sense, the development of the internet was a fulfillment of that plan.