Unions in Europe represent individuals and not companies. Anyone who wants can join a union and let the union represent them. Therefore there is no point in trying to hurt unionization efforts etc, because there is no switch to flop, workers will slowly go there if they feel they benefit from it.
The problem is that EU cannot be considered as a whole. What you see in particular markets can largely differ one from another - what you have in UK, doesn't apply to France. What you have in the latter, doesn't apply to Germany, and so on...