Board Thread:Versus Debates/@comment-34277398-20180509212801/@comment-32685487-20180510175848

Obito knew Itachi was holding out for Sasuke, he also knew Itachi was keeping tabs on Akatsuki and leaking the information back to Konoha secretly. If Obito could kill Itachi he would have, just as he was about to do to Taka for betraying Akatsuki. Difference is he knew he couldn't kill Itachi so he didn't try, and if he tried offscreen it obviously didn't work.