Rhubarbodendron makes several good points. In particular, the "conservatism" and limits of exchange on information. However Hitler did encourage, and allow for, radical ideas implimenting his vision. For example: the concentration camps. On the other side of that very same coin, however, Hitler was completely uninterested in the pursuit of the Atom Bomb and the Nazi Party never pursued it. The problem with saying "what if the Nazi's hadn't been defeated," is that, as Germany practiced it, anyway ... it was, very much, a product of its time. Specifically, of Hitler's time. He's what Naziism meant.
Hitler was also more interested in the advice of his Astrologers than that of his Generals. He had absolute power, in the party, but he seldom used it. Rather, his approval of radical ideas suggested to him by those around him was the way everything was kept in play. The Party Leaders and the Generals were, more or less, kept continually gratified in this manner. Once Hitler died, whether by assassination, or old age, that system would've failed, in short order, because his approval and favour was the end goal. All Hitler really cared about was the security of Germany, his seat in power and culling the population of those he despised. That's where he wanted all resources directed towards - including the sciences. He was a bully and proud to be - and so were those he surrounded himself with.