Catch here is to know what is relevant technology.<p>In 1935 USSR was pioneer in monoplane fighters with retractable undercarriage. They we&#x27;re two or three years ahead of anybody else, and the Russians had them in relatively large quantity.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Polikarpov_I-16" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Polikarpov_I-16</a><p>Problem was that they didn&#x27;t know it was relevant. When war started they still mostly relied on biplanes. And only got the development rolling again in 1940 with MIGs and they could not compete with Nazis in the sky on even terms until 1943.<p>Japanese had total miss with Yamamoto class ships. Germany didn&#x27;t invest enough in submarines and their tanks we&#x27;re way too fancy for field repairs. Nobody understood how important submachine guns would be. Brits had some major naval defects, exposed by explosion of HMS Hood and problems with guns of King George V battleships. France and U.S. fucked up tank development. U.S. made thuderbolts, which we&#x27;re about twice as costly and difficult to built than what was necessary.<p>It&#x27;s complete hit and miss. Currently U.S. has global military hegemony because they can afford to miss more than anybody else. Also logistics. If you are committed to get more stuff to the front than the enemy, you can compensate quite lot.