> Isn’t ending the filibuster a one-way trip also?

Given the history of Senate rules, probably not. We’ve gone from “simple majority to end debate” to “unlimited debate as long as any one Senator wants to continue”, to a 2/3 supermajority for cloture (which, in the time it has existed, has changed both how it is applied and which votes it applies to.) The change hasn’t been unidirectional, and any future change would have no special reason to be assumed to be. (OTOH, neither does the one-way ratchet rayiner initially described exist, so I guess the two are equally real.)