How to "flatten" a pivot table?

[#1]

Good day,

I'ld like to know if there is a simple way to "flatten" a pivot table (merge all dimensions in a single column, like a straight table with sub-totals).

I often have a case when my client wants this kind of table:

displayed "as it would be displayed in an hand-made Excel document":

Here, I have only 2 levels of dimensions, so pivot table is still readable. But when I have 5, 6 or more levels, the pivot table is just unreadable because there is not enough space to display the values.