Has? No. Should be? Probably.
I don't agree. Sure, if you want to write that style of story, that's fine. But there are plenty of books where this isn't the case. Within the fantasy genre, I suspect most books contain details that aren't relevant to the thoughts, acts, or pronouncements of the characters. If you look at classics, this certainly seems to me to be the case.
So no, I don't agree with 'should,' either. Some people prefer to write in a more descriptive style. Plenty of fantasy books, for example, may make mention of a type or tree, or plant, or passing animal that has no bearing on the story or direct relevance to the characters whatsoever.