Because Steph disappeared and didn't play well? Also, it is because Steph attracts defenders like a vacuum even when he is sucking and gives his teammates crazy open shots. Thus he is better for his team to play well. Lebron typically does pound the ball antics, so when he ends up sucking his whole team is ice cold and they don't know what to do since his style doesn't allow for a full team offense like Curry's does. Kind of a James Harden effect. It was why the Miami team did pretty darn well, he wasn't allowed to control the coach and they actually played with a pretty good team offense. Imagine that, he also had hall of famers playing with him to make him look good and hit big shots when he couldn't.