If everything's so simple and obvious, where's the catch?
Don't worry, there's no catch. Just a consequence you need to be acutely aware of: when your process sequences are largely free of waste thanks to the above principles, disruptions have a much more immediate and serious impact! You no longer have the backup inventories you used to be able to draw on.
Then disruptions are often attributed to the new philosophy and it is blamed for them. But that's wrong.
The problems were already there before the changes. The difference is that they weren't noticed as much because the lower production rate made time losses less obvious. The consequence for you is that you must urgently safeguard what you have achieved to avoid disruptions as far as possible!
You need to focus on the two main factors behind disruptions - technical and quality problems - and aim for the greatest possible security against them.