Unions are necessary, as we see when we look at the US. As productivity has increased workers are receiving a smaller and smaller piece of the resulting wealth. Not coincidentally labor is less organized now than it has been in almost a century. If you have power you get resources, simple as that. Individual workers usually have almost no power - they may get a little bit of power temporarily when their skill is heavily in demand but that isn't enough to counteract the inherent power imbalance capital possesses.