I think we'll break the association between sex and gender, and we'll create contexts of more-than-two human genders, but types are too popular a feature in programming languages for me to believe that genders will ever find their way out of human languages--they both provide useful ways to reduce uncertainty while making concise references.

If everybody is a "they" then pronouns become less useful. Maybe we'll go through a stage like that while we rebel against binary-only gendered thinking, but eventually we'll want useful pronouns again and we'll reinvent gender.