One of the researchers at the Max Planck Institut wrote an article in 1995 describing EU social policy as neo-voluntarism.  Basically, because there was not equivalent of the national social policy regimes at the EU level, the end effect of the posted worker's directive and the like was to undermine any social protection.

Ironically, this is much more severe in places like Germany and Sweden where much of the wage regime was set through collective bargaining agreements at the sectoral level.  The only wage restrictions that firms posting workers have to respect are national minimum wages.  

So, no state based minimum wage = no minimum wage. And it's the same for all labor protections.  The only way to get past this is either to institute legislation at the national level and pull away from the project of integration, or to start a serious EU social program.  The business interests that have pushed for integration as a way to break the power of labor discount the possibility of the latter.

I tend to think that what will happen is that they are going to push to far, and there is going to be something like happened in France during the late 1990s(?) when there were attempted labor reforms.  The voice of the people will come from them yelling in the street.  And EU labor legislation will be the result.  It won't be nearly as strong as the old stuff at the national level, but it will be a major improvement over the present push to no labor protection.

And I'll give my consent to any government that does not deny a man a living wage-Billy Bragg