Unicode started with the mission to encode all characters needed for written communication in the world. This was already broad, but was not unusual for its time. Unlike Wikipedia, Unicode never went through a battle between inclusionists and deletionists. Moreover, with Han Unification it strayed from its core mission to "encode all characters needed for written communication in the world" (emphasis mine).
Instead it ended up as a fancy clip art library that every software somehow has to support, but with no way to implement the standard in its entirety.