Is There a Minimum Level of Corporate Concentration?

Is there a minimum level of corporate concentration that needs to exist in order for an arrangement like that to work? And then, more broadly, how much of the decline in unionization across rich countries does have to do with the fact that sort of industrial industry is just a smaller and smaller part of the over all economy? E great questions so on the over all corporate concentration. I think, in some ways, it reminds me of galbraith's work. He was basic eter. The galbrathian vision of an economy was one where there were a handful of very big companies, and them very strong unions that were bargaining with those companies.