There is a communications gap between content strategy (strategists) and content management (executioners). Content architecture can serve an important role in bridging that gap to enable businesses to think strategically, yet execute tactically.
Content strategy needs content architecture (and vice versa). Content architecture allows ideas to be presented, challenged and approved prior to production downstream by bringing different teams and IT together around a common communications framework.
Content architecture is the specification for a content management solution. It is not a replacement for content strategy. Far from it. Instead the aims, audiences, publishing needs typically captured as part of a content strategy, are key, but often missing inputs to content architecture.