I would suggest that this "rule" - as well as many others - is better viewed as an advisement, rather than a hard and fast requirement for a successful photograph.
Is it suggested that there *must* be a single "point of interest"... or can there be "many" ... where the observer's eye is directed in some form of progression? If so, each "point" will be less dominant ... and in many landscapes, I would be hard pressed to select a single "most important" one.
Come to think of it ... I think the idea of a "directed, progressive interest" is far more common, and important, in photography ... and other forms of art ... that are considered to be "great".
Landscapes come to mind most rapidly .... there are other instances where "patterns" become the essence of a significant photograph ... and of course ... that free field we call "abstractions".