That's right. It's the right to decide whether or not I stay alive.
Says who?
Says me. It's my life, and no one else's. I'll live it as long as I like, and not a moment longer. If the day comes that I am terminally ill and face a hopeless, painful and lingering death, I'll take my own life whenever I damned well please and with all due respect, I really don't care what you, the State or anyone else has to say about it. Interfere with such a man at your own peril, because he hasn't a thing to lose except his own suffering.
Go ahead and take your own life, then. But don't force government to sanction it.
And you still may, and you do not need the sanction of the state to do it. All you would need to do, God forbid, is simply purchase a firearm and carry out your wishes. After all, who on Earth could punish you for it after you have already departed? However, do not expect the state to sanction suicide by permitting doctors to serve as executioners.
In the meantime, you are still free to set up living wills and springing durable powers of attorney to let your wishes be known in the case you are incapacitated. You may and ought to do so now, so that your wishes may be followed should you be unable to perform that final grand design on your own life.