Engagement and Performance are both key areas that a manager must manage. An organization filled with folks who hate their job or who are unable to perform is headed for disaster. It really is quite unfortunate then that "Performance" and "Engagement", despite their importance, are incredibly squishy concepts that depend on unique efforts and experiences of every member of a team. This presents a daunting challenge to managers, that few appear to be meeting well.
However, this may be because the tools that we use to approach problems within the workplace lead us to the wrong conclusions about how to achieve important, but squishy goals.