Instead, they contract with academic and industrial researchers to work on specific things that are (or might someday be) of particular interest to the DoD. Thus, if there's a huge DARPA-funded breakthrough in Probabilistic Programming, it's going to have (say) Frank Woods' and Oxford University's name on it, not the DARPA program manager's. The final work might not even be published. They're happy to fund industrial groups if that lays the groundwork for products that the DoD eventually wants to buy.