Because the Ultimate Reality is Love, and not Void.
It is possible to get to a non-dual state of Void, where everything is One, and that is the same as Nothingness. In that state, what you say is true -- there is nothing to do, nothing to say, even no one to be, everything is the same, there's no point to anything. That is also close to where one transcends personal karma, and "you" are not responsible for your actions anymore -- so if you want to be selfish and seize all power, you can if you want, since "it doesn't matter".
But that is not the Ultimate Reality, because it negates all other positive qualities of Divinity -- Love, Beauty, Truth, etc.
And who is to say? The enlightened avatars and sages who have gone before us
