War profiteering isn't anything new
Sun Tsu warns of the danger of fighting long-term and far away battles. The primary concerns are morale(which naturally dampens as soldiers spend more and more time away from their homes and families) and supplies. The cost of transporting supplies strains the treasuries at home, weakening the domestic economy and merchants near the front will always come with supplies, but will sell them at exorbitant prices - knowing that the commander will not have a choice but to buy. War profiteer is therefore as ancient as war itself, wherever there's been war, there have been peddlers who make their fortunes at the expense of the armies and territories that field the armies. The ultimate price is paid by the warring territories, and their people and the costs can run high for a prolonged conflict. Modern technology has resolved the supply line issues but have created whole new ones. Modern supply technology is expensive and advanced. Therefore only a few developers have the resources and technology to produce them. Therefore the companies with the technology replace the merchants hanging around the front lines seeking to make a profit. This form of profiteer creates a whole lot more wealth and concentrates it in fewer actors and is unavoidable in long-term conflicts. So war profiteer is here to stay despite our advancements. No longer is distance the main issue, it is time. Planning, quick resolution and the support of neigbouring allies is key then to solving the issue of reducing war costs. While planning does not eliminate war-time profits, it can curb them to the point where they don't make a huge impact on the economy.