Y'all know what's gonna happen, doncha 'ya? DARPA will perfect the technology, the price will come way down, it'll be widely available in the civilian sector, but there'll ALWAYS be some lout at the theater who will insist on carrying a loud conversation on his cellphone in the middle of the movie! :-P
And some suits of big corporation who claim that they did it all, stealing credits from DARPA. Without DARPA, some billionaires would never existed.
DARPA can take bolder trail-blazing projects because the bottom line they face is not profit but survival. You cannot discount the role of military competition in creating high-tech industry. In many cases, military does initial innovating, which is most difficult. And private sector later commercialize them to be useful consumer products.
In discussing modern economy, we heard a lot about the latter, but little in the former.