If I were to defend the opposite point of view, I would say that inspiration through fiction is only one of many sources, and it does not necessarily constitute an overarching category for practical tools like travel guides.
It is important to acknowledge that fiction can be a powerful trigger, but it is not the only one, nor always the first.
A guide, with its attractive visuals and concrete suggestions, can be the first spark for many, long before a film or a book is consumed.
For example, seeing breathtaking photos of a national park in a Belgian travel guide on the Ardennes can create an irresistible desire to go there, without any prior literary influence.