Indeed, hence the curiosity. The article (both title and content, and the original title of the HN post before it got changed for some reason) claims that every story follows one of the proposed six plots, and the lack of any discussion of non-novels betrays a narrow definition of "story" in order to justify that claim.
Even revising the claim to "all novels follow these plots" is surely easy to disprove given the relatively small sample size compared to the sheer abundance of novels written, but at least it wouldn't try to assert specific literary structures on non-literary forms of storytelling (and even some (quasi)literary ones; I've encountered a lot of fanfics with Mary Sue characters who experience no change in fortune at all!).
Any television series with a plot arc is going to have multiple stories occurring simultaneously, starting and ending asynchronously. Each of those stories will likely follow a valence arc like the ones described in the article if analyzed independently.
Even revising the claim to "all novels follow these plots" is surely easy to disprove given the relatively small sample size compared to the sheer abundance of novels written, but at least it wouldn't try to assert specific literary structures on non-literary forms of storytelling (and even some (quasi)literary ones; I've encountered a lot of fanfics with Mary Sue characters who experience no change in fortune at all!).