Managing and leading software product development

I have been contemplating the roles of the development manager and the product manager in software development. In particular who has what responsibility?

I recently read something that resonated with me, that leaders are needed to bring about changes and managers are needed to create order out of chaos (complexity). The point being made was that both roles are legit, but require different skills and have different end-goals. The tools of the manager are processes and structures while the leader uses motivation through values and emotions. The goal of the manager is to accomplish the plan and that of the leader to achieve the vision.

In software development it is necessary to decide on doing the right thing and then do it right. To achieve this we both need leadership and management. But how is that best put in place? It is tempting to consider this best done by having a leader-manager. I, however, think it is generally too much to ask for in one person (even though they no doubt exist). In my view the role of the development manager requires more management than leadership, and that the opposite is true for product management.

Development managers should not be pure bureaucrats without vision and the ability to motivate people. They might have the goal of bringing structure to the work but they will not succeed unless what they propose is accepted by the organization and the teams in particular. To accomplish this they might need to find novel solutions and be strong in communicating and negotiate for those. The development manager must not buckle the leadership of the product manager by wielding his official authority (embedded in the org-chart).

What I am getting at is that I don't think that management serves the derogatory conjugation it has had. Leadership and management are both necessary ingredients to successful software product development.