It's actually the other way around. The Uchiha were gonna wipe out Konoha with kurama. Itachi saved Konoha by stopping the war.

.......did you actually "comprehend" when you read the manga?
That was Obito and Madara's plan. Not the Uchiha clan as a whole. Though sure they would probably do this anyway.
OT: Yes the Uchiha are/were the most powerful clan in Kanoha. But there are too many exceptional Shinobi on the leaf, a few old clans, (at the time) 2 of the 3 Sannin at their disposal, a powerful Hokage, ANBU/Root
And you would have Uchiha sympathizer sad well as the Uchiha clan. But not every Uchiha is going to have a Sharingan so I'm the end the Uchiha would be overwhelmed and destroyed, hey would indeed probably release Kurama in a final emo moment to go down fighting then Kanoha as a whole would probably just collapse.
It's better this bloody manner was handle discretely and silently as befitting ninja, no?