Sorry, you are greatly mistaken. If the structure of film isn't adhered too we wouldn't understand what was happening on screen. You may not see the structure, but you do know it. For example, ignoring characters and story (kinda), do you know what the rule of the line is? Why it shouldn't be crossed (unless for very specific purposes)? Any idea about eye lines and their importance? Any idea how those 2 very specifc rules impact the story told? How they are used for character?
They are just 2, very important examples of film structure. It exists, it's important. I will even say that bad scripting effects the use of this.
As for scriptwriting, I could go on forever about the importance of a good script in building a product. It's the bridge to the otherwise, build it badly and no one is crossing it. The characters will fall and die, they'll never get to their end conclusion and neither will many of the audience. We, as an audience, understand things in a specific way. As do actors in reading and interpreting a script.