Who besides IT is going to score 20 PPG? Don't we need another guy who is a nightly threat for 20? Bradley may be an outside threat for 20 but has never been a guy who brings it every night on offense. Neither is Smart, Kelly, Jae, Amir.
C's consistent D and respectable offense gets them to 50 wins, but they need optimal consistency offensively to win 60, never mind 65. Think of how consistent, and top-level, the performances of Bird, McHale and Parish were. Same for PP, RA and KG. Same for Draymond, Steph, Klay and KD.
The C's need to KNOW they will put it together on offense night after night after night. On rare nights that a teammate has an off-night, the others WILL step it up. This not the C's yet and therefore they don't look like a 65-win team. Yet.