He came to rid the world of sin and the work of the Devil. He was able to open the way for sinners to get to God the Father. He cleared the way and helped sinners gain salvation!
But Jesus died! He died shamefully, rejected by both man and God! How dare you call him better than past high priests!
But that was the life he came ready to live. His rejection ensures that we never will be. Jesus never came to become our great physical high priest, but our predestined high priest who sits at Gods right hand, interceding for us every day. Jesus died to attain that perfection.