In a recent game the one ultimate AI (Drath) did not use tech trading really. They had a huge research advantage in comparison to all opponents and could have won easily, if they had traded techs and if they did not go for ship tech only.
They just gave me the time I needed. I do not remember something like that before on higher levels. It has been a while, that I played DL. Is that a usual behaviour for Draths, playing DL patch 1.4?