when will be people realise that the ONLY person that can and will beat Itaachi is Sasuke.

As to whether he will kill him or just beat him up untill he realises he was wrong I dont know. As to when it will happen, I dont know.

But there is no other alternative. Sasuke will beat Itachi.

It wont be Naruto, it wont be Jiraya, it wont be oro, it wont be Tsunade or anybody else.