The Relations Between Project Management and Selling
Project management involves quite a bit of selling. There will be times when you'll have to rely heavily on your ability to influence others, to sell an idea, sell yourself, sell your project, or perhaps sell the virtues of project management.
In a perfect business situation, every project should prove its associated benefits in a business case, qualitative and quantitative. But too many projects start and move far into implementation without serious scrutiny: after such project begins, there is very little chance that it will ever succeed. A major reason for this is that if marginal projects are approved, there is likely to be insufficient allocation of always scarce resources. The project then has to "sell itself" even after it is approved: is the investment worth continuing?
That's why many companies have moved toward project portfolio management, where each new product project is viewed as an investment. Here, tough go/kill decision points are built into the new project process in the form of gates that successively cull out mediocre projects.
Source: Benefits Realization Management, a Practice Guide (2017), PMI.