This structure has evolved to be incredibly effective at capturing our attention. In other words, this structure is sticky.
It feels like modern movies are more often starting to shy away from the standard hero's journey structure. I've been seeing more movies lately that follow more unpredictable and unique stroytelling structures which I feel is a good thing. The problem with the Hero's journey is that it gets old fast. I personally would get very bored if I saw another movie that followed this exact structure because it has been used so many times before. I want to see something more chaotic like our life often is.