Assassin vs assassin is stupid and boring. It's either one of the opponent is new and don't know the ropes and then he's going to be steamrolled or both know basic ropes and then the fight goes like you describe. Of course at some point everyone can make fatal mistake but the chance is low and gets lower with basic experience. So it was more productive to avoid fighting you and stay hidden for others where I could use assassinate and mt to its max power.