Most leadership transitions fail not in their content but in their cadence. The decisions are, broadly, the right ones — the role design is sensible, the new leader is competent, the organization understands the rationale — and the failure is in the rhythm of the transition itself: the speed with which authority is transferred, the visibility of the outgoing leader during the transition period, the small daily decisions about which meetings the new leader chairs and which the outgoing leader still attends.
I have observed enough of these to have formed a working view, which is this. The transitions that succeed share a deliberate cadence: the outgoing leader's visibility tapers on a defined schedule, the new leader's visibility increases on the same schedule, and the schedule is communicated openly to the organization. The transitions that fail share a different pattern: the cadence is implicit, the visibility taper is improvised, and the organization is left to read the signals about who is in charge from the seating chart at meetings and from which executive's email signature appears on the announcements.
The right cadence is not difficult to design. It is, however, difficult to execute, because it requires both the outgoing and the incoming leader to subordinate their personal preferences about visibility to a discipline imposed for the organization's benefit. The transitions that succeed are, with notable consistency, the transitions in which both leaders accept that discipline. The transitions that fail are, with the same consistency, the transitions in which one or both leaders depart from it under the pressure of the moment.