During WWII some long-standing military disciplines (biplane fighters, battleship duels) went extinct. Others (submarines, radar, jet engines) were in a basic state in 1939, then highly developed during WWII and important afterwards. Still others (ballistic missiles, nuclear weapons) were entirely developed during WWII and important thereafter. Many, many other technologies were experimented with during WWII, failed for whatever reason, and were abandoned.
There is a final category that might be considered. This is a very tiny number of technologies which were developed entirely during WWII, actually worked, but were already overtaken by the time WWII ended.
MiG’s unique late-war fighter project would fall into this final small category. This plane was originally called project “N”, then I-250, and finally MiG-13.