40 years? You are wwwaaaayyy short VV!
ss couples have clearly covertly existed since human history began. However, for some reason, not a single culture ever accepted them from start to finish. No where did calling ss couples 'married' pop up, establish itself and spread.
The other examples you list? Been around and practiced in many places.
Quite an astounding difference.
Thing's change and right now
We're all becoming