Weapons in space, yes. Government constellations are SpaceX's best opportunity. As for anything else, the market for anything bigger than Falcon 9 is very small. Elon Musk didn't even want to proceed with Falcon Heavy because there isn't much market for even that, but Shotwell managed to convince him that having Falcon Heavy would actually help sales of Falcon 9, by inducing the government to take SpaceX more seriously.