How the Senate filibuster got screwed up

In cutting the cloture number from 67 to 60, a good thing, the Senate, for compromise or whatever reason, radically redefined the word "filibuster," as detailed here. And, hence, we are at where we are today. But, the next Senate could, as part of start-of-session rules adoption, if nothing else, change that, I think. Why it didn't, this session, I have not a clue.