Well, you know why that's a problem, don't you? The legislators who decide what public funds should be spent personally profit from those decisions. In the case of military spending, big corporations write huge bribe checks so that on the micro level, they will get federal contracts; on the macro level, a persistent state of high tension and conflict will exist.
Trump has broken alliances, alienated friends, and made enemies out of neutral parties. He's shown the world that his word is worthless. Thus, he's created the very situation Eisenhower warned about--a self-perpetuating need for more and more and more military hardware. Tensions and insecurities where none existed before. All because the bigly stable genius is an insecure bully who only knows one approach to foreign relations.