German’s overconfidence in their “unbreakable” enigma machine surely contributed to the Allied cryptanalysts’ victorious over German cryptographers. At the same time, other key driving forces that might have enormously contributed to the success of the Allied cryptanalysts were their consistent sense of insecurity and fear of being defeated in the war.
While the allied first laid back and lost their cryptanalytic zeal believing that Germany was no longer a threat, Poland, as a newly formed independent state, realized the danger of being in between Russia and Germany and therefore, at the time, any information regarding the two enemies was highly valued by the Poland cryptographers. The Poles tried everything they could to attempt to make a progress, including forming a new cipher bureau, employing a clairvoyant and paying to make Schmidt turn traitor to German to provide the information for the Allied to create a replica of the Enigma machine.
Similarly, after Poland shared Rejewski’s bombes with the Allied, the Bletchley Park was formed and the continuous evolvement of the enigma machine motivated this group of talented people to keep taking risks, being creative, pushing and exploring the boundaries in order to break this seemingly unbreakable enigma machine. They tried to figure out any weakness not only of the enigma machine but also of those who used enigma. With German’s overconfidence and the Allied enormous effort driven by the fear and threat of being kept in the dark from German, eventually Allied cryptanalysts victorious over the German cryptographers and ended the war earlier than it could be.