It's a lot like fiat currency, it has respect of "all". Parties know if they kill the filibuster, the next time that the pendulum swings back everything they did will get thrown on the trash heap.
There is an element of truth to this but we’ve seen the filibuster selectively weakened to accomplish a specific goal under Mitch McConnell as well as Harry Reid before him. Its been done by both just within the last 2 presidencies, and there’s no good reason to assume your opponent won’t be the one to do it first when it suits them.
