It is true that there is (at most) one status quo at a time. Further, I would expect the dominant morality of a particular moment to support the status quo, but that doesn't imply that only one moral system is believed at any particular time.

I don't know what you mean by asserting that there is only one status quo - it seems false. The status quo in France in 1788 wasn't the same as the status quo in France in 1791.

Further, there's nothing inherent in the concept of a morality that requires it agree that the current state of affairs is best. Mencius Moldbug has a morality, and he thinks the way western nations run their affairs is filled with nonsense.