many (or most) conditions in a pricing schema are own customized. They may have equal attributes like some standard conditions, but the real difference of the meaning is just coming from the description. You can have several conditions in one schema which reduce values. SAP cannot know whch one should be in such a report and which are excluded.
Any standard given report would not really fulfill the expectations of most customers
one would like to see the conditions horizontally arranged because he uses only in total, other could never agree as the have maybe 2 conditions in their calculation schema.
in general you would need a customizing to tell how this report should look like (maybe similar like it is for the MMBE layout), but if you define in customizing or directly in a query does not really make a difference in your effort.
So it is just economy for SAP (saves development hours) not to provide something that is finally not used and replaced by own reports.