Considering the many infrastructure projects in Germany that got derailed massively (neue Rheinlinie, Lindau-München, München-Berlin, etc), took ages to build and overshot budget tenfolds (Say Hi to Hamburg) or aren't even yet started (or were abandoned like the Maglev in MUC) or ended up in disasters like in CGN where the public archive was destroyed while building the metro..

I don't think there is any German efficency in public works. The private sector does profit massively from the undervalued Euro (for Germany) and basically being in the same currency union with countries having MUCH weaker economies.

Processes in German companies aren't really efficent when compared to other countries that have hard currencies and therefore had to optimise much more (like Switzerland) and are able to compete with Germany despite much higher wages.

In fact, if the Euro breaks down and Germany gets back a (much stronger) Deutsche Mark, they'll be in heavy trouble all across the economical board.