Is succession planning still relevant?

As change has become a more evident reality in organizations, there are fewer durable, albeit honest, promises leaders can make to people who want to stay or move up in the organization. The promising leaders at the top themselves churn in ways that makes promise discontinuities more likely.  it becomes more unrealistic for any emerging leader to expect promises or delivery on promises of succession opportunities. Mobility and opportunity availability makes it more possible to emerge into leadership positions in other organizations.