The concept of lean started out in manufacturing in the 1980s and was focused on the elimination of waste. Now we try to "lean" everything. We have lean in healthcare, in banking, in pharmaceuticals and every other industry.
The problem with lean is that it focuses on the removal of waste and the preservation of value, but not the actual creation of value. Lean is too often used as a methodology and not a mindset. Organizations focus on tools and methods, not changes and behaviours. People are trained on the "lean methodology" but not so much on the "lean mindset."
When you focus on tools and methods, you become a slave to them and remove all thinking about growth and value creation.
Lean is an effective way to increase productivity for repeatable tasks, but it doesn't help to develop new ideas or strategies.
If you think lean is the answer to achieving operational excellence, you will be disappointed with the results. Operational excellence comes from the ability to relentlessly pursue improvements in performance and profitability by focusing on value for the customer. Unfortunately lean provides a much narrower focus than that.