Board Thread:Theories and Speculation/@comment-34656247-20180531072459/@comment-6769189-20180604230912

FlatZone wrote: Obito made it clear afterwards that if Itachi wanted to kill Sasuke, then he would have, this is literally stated by Obito in the manga. Itachi was holding back even while sick.. So there goes your headcanon. Itachi could have killed him yes but that doesnt mean he let him escape techniques and attacks. He was still fighting for the win, not the kill. Just because he didnt want to kill him doesnt mean he would just let him counter/escape his attacks. Sasuke showed himself to be strong enough to escape Tsukuyomi and clecer enough to escape Amaterasu but had nothing to counter Susanoo, which makes Itachi virtually invincible.

Just because Itachi could kill Sasuke anytime he wanted with his strongest technique doesnt mean he could have killed him with any technique in his arsenal.