Are you forgetting that Itachis MS eyes is within Sasuke, thats how he obtain EMS.
Transplanting someones eye will give the person the abilities of those eyes, just like how kakashi got the same ability as Obito.
They inherit powers, not the guys weapon. The picture of sasukes susanoo above with it, is wrong.
"In the anime, the final form of Sasuke's Susanoo was erroneously depicted with a gourd in its secondary right hand."
I know that quote is from naruto wiki, but Itachi was the wielder of the blade, just because he had it doesn't make it something that passes on like the ABILITIES of amaterasu and tsukuyomi, it's an ethereal weapon, not an ability.