So, when we're the various nationalisation programs put into effect? I know some prominent industrialist were already close to the party, even before they became the de facto state.
Some industry had in fact already fell into state hands prior to the Reich, specifically those which were failing in the economic climate, but as that was (as I understand it) a trend in many countries at the time.
@{ Emilia } could doubtless fill in the gaps better than I could but state sponsorship and/or takeovers of several industries key to the upcoming war effort grew exponentially throughout the latter half of the 1930s, leading many at the time to foresee exactly the model you propose, especially given Hitler's seeming antipathy to free markets. Steelworks and motor manufacture (as apparently you already know) BUT heavy restrictions were put into place regarding civilian motor vehicle manufacture, freeing up resources for military expenditure.
Throughout this period the unions were effectively eliminated, in many cases violently, with most forms of industrial action being outlawed. Their state controlled replacement the DAF did in fact promise good working conditions but only on the promise of absolute allegiance, often with the added proviso that gaining employment without membership became increasingly difficult as many nationalised industries began requiring membership as a precondition for employment.
You see the pattern? Policies which superficially look pretty much like socialism were put into place, but as a pretext for dictatorship. Peacetime rights were ensured, but only for those who were loyal, whilst industries were nationalised in preparation for wartime re-purposing. All throughout this period military spending rose at an even faster rate than public sponsorship, all laying the groundwork for building the war machine.