They wan't to win......simple as that!
Vissario said:That is an entirely different reason reserved for end game.
Personally I think that it is a statement that is made depending on your overall standing. Its not just about techs! the ai takes into account culture,size of your empire,reserch rate,/wonders/ buildings in cities,military power.You are too advanced is an overall perspective of your civ.
MrCynical said:Each civ has a different threshold of tech trades after which they won't trade any more
Alraun said:Leaving my only option as destroying them? That's not very bright!