Thats true and I don't want to defend this in any way. But its a way to understand why SAP is like it is: the "core" you speak of is already fragmented and by

Thats true and I don't want to defend this in any way. But its a way to understand why SAP is like it is: the "core" you speak of is already fragmented and by chance, it can even happen that this core knowledge is invalidated by something further down the stack. Documentation of 100 edge cases wouldn't help you much in that regard. As others have stated, the oracle world is not much better in that respect. Its a way to understand why anyone would even buy such "crap". Because thats the crap that solves the customers problem somehow and there is no competing company that would even come close to offering a similar service. I don't mean to imply that no one could ;).