Interesting opinion and I main agree.
As you know, Scrum is currently the mostly used Agile development framework. It focuses on team organization (self-organization actually) rather then on precise Engineering practises. In the basic Scrum training (Certified Scrum Master), we learn that project managers do not exist in Scrum.
Their role and responsibilities are spread between the self-organizing development team, the Scrum Master and the Product Owner.
Therefore, the Project Manager of Scrum projects should just accept that he is not a project manager anymore and embrace his new role which is more likely to become a Scrum Master or a Product Owner depending of his skills and affinities. It is a tough change.
Therefore, in real Agile/Scrum development organizations, project management is present, effective and efficient but clearly implicit since the Project Manager as a role itself should just not exist.
It is much more simple and honest to define new roles then try to recycle an old one.

Julien.