The thing about Lovecraft was, mortals are not exempt: there is always, ALWAYS something bigger, stronger, and more alien than the last guy. The Chaos Gods are just manifestations of our own baser desires - potent and maddening, to be sure, but still based on what we understand at our most primal levels.
The "Elder Things" of Lovecraft are the complete opposite. They aren't evil per se, they simply don't comprehend such things as morality and mortality. Its presence destroys us the same way our own presence destroys bacteria in our intestines: we aren't aware of it on any level, it's just the way we are.
And anything that can just sweep the galaxy clean with a stray thought like that, removing the source of the Chaos God's essence, has automatically won any battle. The galaxy is emptied and the Chaos Gods dissolve back into nothing.
...Then the Elder Things are themselves consumed by their own "Chaos God" equivalents from the Warp, beings so immeasurably frightening and unnatural that they corrupt the Elder Things. And they themselves are destroyed when something even worse shows up. The cycle goes on. Even death may die.