Will require the Church's position as a whole to have changed, not just some breakaway priests or bishops beginning to perform these marriages.

This would likely take the form of a release by an "apostolic constitution" released by the Pope, perhaps following an ecumenical council, though any official statement of doctrine made by the Church indicating that priests may perform same-sex marriages will be sufficient (e.g. in the official catechism or similar).

In the event that the Catholic Church ceases to exist or substantially changes in form or structure, such that I do not believe this market can be resolved consistent with its original spirit, I will resolve it N/A.