Its not the extinction of binary, just realizing that there are people in between the binaries.
People tend to have reductionist view of the world; what's normal for them because
biologically their sex and gender is congruent and they are attracted to the opposite sex,
is the norm for everyone and they impose these norms culturally. People become
myopic to everything but their own worldview.
Even in non oppressive society, peer pressure, taking society as a whole as a peer, exists
and the human being wants to be part of something and not be alone. So, for those
who nature has placed in a strange place culturally and biologically, the desire
to be part of the community and be like others conflicts with the inner desire to be
what we truly are. In a sense TS have it easy, because they can rejoin this majority
community, while those in between (CD, Androgyne, etc)
have to find their peer and build this community that they want to belong too.
The STRICT binary construct is cultural point of view. It is the one that is very
slowly fading. But, since gender is not a lifestyle, and is a biological imperative
overlaid and amplified by sexual identity, it cannot fade. It can only morph
into another form, less strict but still there. Boys will be boys and girls will be girls
and then they'll be all the others, finally revealed in all their beautiful form.