Traditional defense contractors have low profit margin because of the cost plus pricing on the contracts. They literally are only allowed to charge the cost they incur plus some fixed profit percentage. As such, they have incentive to drive up the costs, so that their profit, while low percentage, is on high base.
SpaceX wouldn’t need to so that. Companies like Anduril already are trying to win contracts on fixed price model, and if they succeed, they’ll have much higher profit margins than Raytheon et al.