If only it were that easy, just press a button and poof, your gone, like you never even exited.
But sadly when we try and take our own lives, that very action runs contrary to every sort of social programming, and evolutionary survival instinct that we have, so we kind of have to battle with ourselves to try and even make an attempt.
but it's also kind of a waste of time thinking about hypotheticals like having a big red button of whatever, as all it does is allow our selves to be mentally distracted from our problems at hand, by giving us an easy solution to fantasize about. One that will happen anyways.