In my experience, there is a fundamental contradiction.
Note first that I understand SCM as an attempt to offer a /software/ answer to the communications challenges identified by Wayne Babich (1986) while applying CM practices to software development (*).
CM is on the contrary an /organization/ answer. It is not an answer to these precise challenges, which rose in the context of CM itself.
Anyway, 'Agile' also belongs to the realm of /organization/. It builds thus upon a (right or wrong) diagnostic of failure of SCM.
The other assumption of 'Agile' which contradicts and denies SCM experience is that communications is ideally co-located and synchronous (face-to-face meetings). While this is obviously desperately non-scalable, the Agile conclusion is to avoid communications, by stating once and for all values and principles, and building upon stable /teams/ among which communications is not needed because it is supposed to have already taken place.
One could also notice that Agile reduces people to mere 'individuals', suited to fill in roles in teams.
* I know of few tools to have taken the SCM challenge, mostly of the original (base) ClearCase. My experience in this respect is that SCM died in much the same way as Object-oriented databases: it never converged to a concept that would have been consistently represented by different products, so that it never gained wide enough acceptance.
Marc
