How did process development suddenly become simple?
Methods and tools linked to Lean is often described as very simple - as common sense. That's not my view. Of course, it is relatively easy to describe and show examples of how 5S, 5 Why, Fishbone, Canoe, Force field and A3 analysis used. But it can also be said of a lathe; The tool itself is simple but it requires knowledge and skill to use the lathe to make the result attractive and useful.
For many businesses, process orientation is a fundamental part of Lean, itself a major challenge. And without process orientation, the use of the methods becomes rather pointless. This aspect of Lean it is rarely talked about.
Other methods and tools can be difficult to understand even in theory. I think of the statistical tools necessary to evaluate processes, for example frequency blue, histogram, stratification and Pareto chart. Where does the idea come from that our nurses, port workers and property managers would have a natural aptitude for statistical analysis and theoretical business planning? It is one thing to look at and understand a well-worked lay-out - an entirely different one to develop it.
Lean is not common sense. It requires professional skills like most things. To succeed, conscious decisions from management and expertise are required to guide the operations in the improvement work.