If I do understand it correctly, True Resurrection only works if the person has been dead for less than 200 years. I assume they picked Astarion's age especially so that True Resurrection cannot work anymore.
Not quite in my opinion. He tells Sebastian he brought him to Cazadors 170 years ago and that he was one of the first. Which would fit as he would likely remember early conquests before numbing his mind as time went on. Unless Caz kept Astarion around doing not very much for 30 years it seems likely to me that Astarion has been a Vampire/undead for well under the 200 year threashold. I always thought they had done this deliberately to leave options open as they developed the game.
