From aircraft carriers to battleships.
German and Soviet tank designs converged somewhat in the 1930s because of the shared experience of the Kazan Tank School. Both international pariahs, Weimar Germany and the Soviet Union began a fruitful collaboration in the late 1920s on air, armor, and chemical weapons. By the time the rise of the Nazis ended the collaboration, both the Soviets and the Germans possessed innovative new ideas for armor technology and employment.
For nearly seven decades, the defense-industrial complex of the Soviet Union went toe-to-toe with the best firms that the West had to offer. In some cases, it surprised the West with cheap, innovative, effective systems. In others, it could barely manage to put together aircraft that could remain in the air, and ships that could stay at sea.
No single weapon could have saved the Soviet Union, but several might have shifted the contours of its collapse. The relationship between technology and the “human” elements of war, including doctrine and organization, is complex. Decisions about isolated systems can have far reaching implications for how a nation defends itself.