$500M? That's the true cost of maybe half a dozen F-35s. Possibly fewer as Lockheed has been under pressure to get the sticker prices down and players in the US Military Industrial Complex are nothing if not cognizant of government wishes. They'll recover any paper losses one way or another. That's the way the game is played.
Anyway, a supercomputer seems to me a better investment than a few copies of an extraordinarily expensive, and likely unnecessary fighter aircraft. And it's good to hear that Cray is still around in some form. Seymour Cray's mid and late 20th century computer designs (CDC 1604, 6600, 7600, etc) were really quite remarkable and were a joy to work with.