I believe he's referring to project managers, not product managers. The latter certainly have a crucial role in understanding how the product fits into the mar

I believe he's referring to project managers, not product managers. The latter certainly have a crucial role in understanding how the product fits into the market, and undertaking the kind of strategic thinking you're talking about. The role of the former, however, is usually to manage work scheduling and intra-team coordination, which, the OP is arguing, is something that programmers can generally handle on their own.