Development in tech is often leapfrog. The Germans had the Horton 226? And a whole load of new ideas they couldn’t bring to bear and weren’t complete. Given another year and resources WW2 would have been a very different ending.
America had the Mustang and a whole load of aircraft that would not have been if not for UK design. They caught up with the help of friends. Friends who are not really doing more than jog along.
Korea was a case in point of USA shutting up the shop and going home to find another war erupting. USA had brilliant pilots against superior soviet aircraft manned by substandard pilots. It was the man who made Korea. Especially as they were planning to disband the marines.
War is fast and now down to moments. China...