It's odd to me that this is how his career has turned out. When he came out, he was perceived as a versatile, well-rounded player - good playmaker, decent defender at multiple positions, capable of scoring in different ways, good at letting the game flow dictate what he did, etc. At the time he was viewed as the perfect glue guy to play with stars (like Westbrook and Durant).
At this point the consensus view from people including him is that his best role is as an inefficient chucker who does little else on the floor.