All recursive algorithms are inherently NOT-inplace, isn't it?
Recursion is an abstract concept. Talking about whether or not it has in-place semantics is nonsense. (Unless of course the language specifies recursion semantics.) This idea is related to how it is nonsense to talk about the speed of a language.

How recursion is implemented is another question. For example, a compiler might perform tail call optimization where recursion can be converted to a loop under the hood among other things. In this case, recursion maintains constant stack space (assuming your architechure uses stacks :D)

EDIT: What does this all mean? It means that there exist recursive algorithms that are in-place when implemented in certain fashions. Thus the statement "All recursive algorithms are inherently not in-place" is false.