His experience of having trouble answering more than '5 why's' is a nice revelation. This is an exercise that nearly every engineer learns about (that started at Toyota[1]) and has become one of the basic tools used in continuous improvement. I often complete the exercise and it is trouble enough to make it to the 5'th why, the thought actually never occurred to me to go farther.
As a side note - when you are improving things, that 4'th and 5'th 'why' are often things that are very hard (and costly) to change.
As a side note - when you are improving things, that 4'th and 5'th 'why' are often things that are very hard (and costly) to change.
[1] https://en.wikipedia.org/wiki/5_Whys