Some humans would do anything to see if it was possible to do it. If you put a large switch in some cave somewhere, with a sign on it saying 'End-of-the-World Switch. PLEASE DO NOT TOUCH', the paint wouldn't even have time to dry.

So why do people want to kill themselves?
-because the world is ruled by idiots, q-shamans, degenerates with hurt ego, people who don't understand science and don't like science.

What would happen if they succeeded in destroying the world?

They would say it is what it is, and then end up like Mussolinni.
Because people can be cruel.