Ditch cost plus contracts and use taxes to curb companies that are just profiting off rent-seeking behavior (like sitting on patents). This was done during WWII, marginal tax rates were set to 100% to discourage war profiteering. Companies would still have an incentive to cut costs, to increase profits. But they'd then be incentivized to reinvest those profits because otherwise those profits would be greatly taxed. Granted, how you'd effectively target these taxes outside of unusual circumstances like a world war might be too complicated to be feasible.