Succession planning is indeed the key, but perhaps not in the conventional sense.
Lean thinking entails meta-cognition, which means 'knowing about knowing' and answering questions like:
How do I learn?
What do I know?
What do I know well?
What do I not know very well?
Great leaders tend to know themselves thereby, and can make conscious decisions.
Leaders need to ask these questions of their organization:
How do we learn best?
What do we currently know, and not know, well?
Most important question for leaders:
How do I ensure that we'll continue to learn, after our current leaders retire or move on?
A tough one, to be sure.
Rendering of the new Apple University campus in Cupertino California
The late, great Steve Jobs thought about it a great deal.
Sounds like Apple University is his posthumous attempt to perpetuate the Apple Way.