He was a highlight reel attacking midfielder who never did much defending, and was not a consistent performer. That works fine in a top 4 liverpool team, but got exposed when he was played as a midfielder at a huge team like Barcelona. Additionally, the game has moved away from luxury players like him and Ozil. Current attacking midfielders like Odegaard, Bernardo Silva, Maddison, and KDB all press hard and have positional awareness.