I wrote a book about it --The Remedy.
Why did I bother?
Because Lean is about reducing waste & variation -- and most of it is outside the factory.
Factories, and Operations in general, have continued to improve the past few decades.
Though there is still much opportunity, in many industries they are no longer the bottleneck.
When you buy a new car, for example, most of the lead time is outside the factory.
Sales, Marketing, Design, Engineering and so on are the "undiscovered country".
How do we support the good people in these areas?
Here are a few questions to get us started.
For each zone, ask:
1) What is waste?
2) What is value?
3) What are some core mental models?
If we can build on these to define our Purpose clearly, we'll can start to pull in powerful Lean tools to help us achieve that Purpose.
(For more on how to do this, interested readers are referred to the book Getting the Right Things Done)