Looking at the other half of this complaint: cannot or will not?
In an age where there's a million things demanding your attention, a 20-page article is asking for a lot of someone's time, and my experience has been that 19-and-a-half of those pages are nearly always filler. The student commenting they kept losing track of what the paper was about suggests the assigned article probably follows the same pattern.
A writer that meanders about most of their article with mostly unnecessary setup before getting to their point in the last paragraph is disrespectful of their readers' time and undeserving of a full read-through, in my opinion.
A common trope I see in longer articles is to give detailed narratives of one or more people's life stories before finally telling me about some recent struggle they've run into, as if I was both interested in their biographies and incapable of empathizing with their struggles otherwise. I can feel bad for someone whose tap water is flammable without having to read they were a girl scout and a national merit scholar who helped a neighbor escape a house fire and now houses local homeless people in their basement.