It was already an industrial superpower, just a very troubled one. Plus you never really got a chance to see how those economic policies panned out in the long term seeing as all those other policies of his made the third reich something of a one trick economy with a rapidly reducing workforce increasingly dependent on rather inefficient slave labour. It doesn't take too much of an imagination to work out that had he been a bit less is more on all that militarism, expansionism and genocide, that public construction works would have run out of stuff to do and some nasty stagnation and inflation would have followed, especially with domestic consumption unable to fill the gap. His lovely Empire wouldn't have done much to solve things long term either, terribly short sighted policies that chap. Well, terrible policies in the literal sense of the word too I guess. This isn't really Godwin is it. China in a few years is facing similar issues thinking about it, all those lovely dams and railways and roads are practically done and that workforce is getting pricier.