Why must a balance exist between project management processes and product-oriented processes?

It is pointless having the best project management processes (e.g. Project Management Plans, Schedules, EVM Techniques, Risk Registers), if you neglect the product processes (e.g. Design Reviews, Agile development cycles, Repair and Overhaul Strategy, Training and adequate Product Documentation, Obsolescence Strategy, Future Enhancement Roadmaps), because you will get to the end of the project ticking all the project deliverables but chances are not having a certified or approved product to give to your customers. Conversely, putting all the effort into developing and designing products without considering project management processes can lead to other problems (e.g. engineers adding wish-list or nice to have capabilities, project overspends, issues associated with lack of contingency planning and mitigation actions, project overspends and delivering late to market). Ideally, projects should have a Project Manager and a Lead Engineer, who work in harmony to deliver the right product, at the right price, at the right time to the right quality. This can only be achieved if a balance occurs between the project and product processes. Over emphasis on one, often leads to an under emphasis on the other.