>>718021528
To me the ending represents the breaking point of history, an event you would see as a beginning of a great change, but after a while you realize it's more or less the same shit all over and nothing really changed that much. Not to get into /pol/ territory, but it's sort of like the elections. One moment people are losing their minds about it as if the world is about to end, and the next day it's back to the usual old routine.
As for the Killer himse;f, in the overall plot the Killer is mostly seen as the imago of murder just as we see Grim Reaper as representation of death, mostly thanks to the immersive theater, and with the theater going down in the end, so did the old image of the Killer. And just like boogeyman of yesterday is replaced by a new one depending on the weather outside, so did the new Killer became what people most often associate with murder, i.e. Killer BB.