I agree that it's hard to determine and that ultimately the value of labour is determined by the return on capital. That's why I genuinely believe that the movement of capital to the Far East and the corresponding increase in wages and living standards is a good thing, even though it has happened to some extent at our expense (and indeed mine since I work in a a sector which is very exposed to Far Eastern manufacturing competition).It was an ambiguous question, like your one. It is exemplified by throwing another factor into the equation "sold in Germany" after the question is answered. I could easily add that it costs twice as much in wages in Norway to do my job. So how much is my labour worth now? Am I paid too much? Or too little?
In the long run the value of labour will determine the return on capital. The more incomes fall, the narrower the consumer base for highly profitable goods and services to be sold. This is what we are seeing today. The dilution of the purchasing power of labour corresponding with increases in asset values and capital investments.
Cracks are setting in, in Europe and the US.
It is also why I don't understand where the notion comes from that pay levels should somehow be tied to the cost of living or what people need, or think they need, to live on.