Hugh being Hugh, demographics comes into his essay at many points. I don't know if I agree with his diagnosis of German wage restraint, but I'd be remiss not to post it:

Essentially mature economies become dependent on export expansion for growth either if they are in the aftermath of a credit driven consumer boom (and hence deleveraging, weakening domestic demand) or their population median age rises above a certain point (yet to be adequately calibrated) meaning that the demand for consumer credit no longer expands as the balance between savers and borrowers shifts across cohorts and across the life cycle. Hence Germany's wage adjustment is not something exceptional, or even reversible, but forms part of a natural process to reinforce competitiveness in the export sector of a society with a large elderly population and hence generate GDP growth.