You're right, socially ascribed gender didn't go away across society, but there was a string conscious effort by many - still is, by the way - to make it go away or at least make it significantly less impactful.

Importantly, the normative consensus among progressives was as GP describes. The trans activism movement is a move backwards in that regard, since it tries to shift the normative consensus back towards gender being important and that gender should be impactful. It's no wonder they clash with some feminists.