It had been years since Bruno first introduced his designs for the concept of a functional tank. What Bruno had conceptualized was a rough draft. It was based upon his knowledge of tanks from his past life, crudely drawn blueprints of a theoretical tank based upon a design from the Second World War during his past life, and of course, his own current functional knowledge of mechanical engineering.
The thing was that creating machine guns, semiautomatic rifles, submachine guns, and artillery pieces was a hell of a lot easier than making armored vehicles, warships, submarines, and airplanes.
While warships and submarines were theoretically easier for his naval engineers to comprehend, as they more or less already understood such concepts, armored vehicles and warplanes were brand new applications of warfare that nobody had really conceived until now, or at least had created a functional design.