Firstly I don’t believe my assertion was that “Workers work more, look at productivity” but that “The disparity between productivity and wages has increased”. Maybe when the labor theory of value is invoked these two don’t seem like different statements, but they are.
As for the question of exploitation, although marx did have an idea of some proletarian morality, the LTV has little to do with morality. I would argue that works are exploited in the Marxian sense, but this exploitation is morally justified since there is value in the work of the capitalist, risk taking and so on.
See the issue is, much like in political freedom, that having the choice to move between one area and another is not the sole determination of freedom. In the same way, having the choice between one company and another, both offering different wages, is not freedom.