People talk about structure a lot. This is a good thing. However, the way they talk about it seems to be very Act-centric. Three Acts. Beginning, Middle, End. Intro, Conflict, Resolution.
That's all well and good, but it seems to be all they talk about. Structure deals with more than the number of acts you have and at what point prior to an act break you have a "plot point." This becomes even more problematic in light of the fact that this Three Act Structure is a prominent but still arguable one. Shakespeare? Greek Drama? Five acts. Most musicals have only two.
The truth? It's all the same. These X-act structures are far from exact. (Forgive me.) They are merely templates to place over a work and aid in analysis. Delineating something into observable acts allows you more convenient points of reference. Once these structures became prominently acknowledged, you can certainly bet that writers began thinking in terms of X-acts in their own writing.
These are, however, masks and frames surrounding the common dramatic situations that can be combined in infinitely creative ways to allow for a dramatically succinct and balanced experience that varies depending on the relative advantages of the medium it's being presented in.
Art is always trying to reach for dramatic content that is more stimulating to our innate humanity than that which is found in nature. This can be found in three and five act structures, but it isn't the acts that are bringing the drama. It's the way the characters interface with the plot to present a discernible theme. Screenplays can follow the guidelines of these structures to a tee, and still fail.
There comes a time when act breaks and plot points must be set aside, and the focus of the writer must be turned to the specific interactions of his characters and how their conflict is telling of the creator's intent. This is where the craft comes in.