Munitions makers and financiers profit from war. They always have. It is therefore in their interests to lobby politicians to pursue policies which result in wars, arms sales, and conflict. That's not a conspiracy, it's the result of monetary self-interest. It may involve a great variety of limited conspiracies by a great many different people, but it's not a single, over-arching, giant conspiracy...it's a way of making profits. Do empires engage in secret strategic planning to further their aims? Yes. They do it all the time, and they don't make it public knowledge. You can call those actions "conspiracies" if you want to...I call it politics and imperial strategy.