This isn't very objective. If you used to work where someone thought that way, do not give them to run a project of nuclear powerplant or something similar.
The project sponsor (as a role) ensures that the project manager is not stretched between that but running the project.
Of course, there are lousy project managers and agile approaches (it happens that I am a project manager AND DevOps trainer and that there is no way in the world I would use Scrum, for example).