You can refuse to eat. Works every time.
It's just that it's a rather painful way to go. That's one reason folks like Teresa Schiavo are in the news. As it dawns on people that the Courts cannot euthanize folks but must kill them slowly and painfully by starvation, the clamor will come for the Compassion that is the needle -- and dignity -- of the dog pound.
I hope you realize how much progress IS being made in this regard. "Food and water" are now known as "ANH" in the legal briefs ... or "Artificial Nutritition and Hydration". Trust me, if you can't demand to eat and actually feed yourself, chances are good the argument can be made that feeding you falls within the realm of Extraordinary Measures like "ANH".
I guess the only part you and the rest of the Deathists are forgetting is that it's only if your Fit Enough that you'll have the option to choose the good death. Unfortunately -- unless rendered temporarily insane by the pain the State refuses to alleviate or the depression that's a Manageable Illness only if you're a Productive-aged human -- most folks don't really wish to die when they're still fit enough to suicide.
The unfit, unproductive and dying will just be offed whether they or the "Life Force" animating them like it or not ... same as the Unwanted.
I too have spent a great deal of time caring for the dying. I have witnessed long, agonizing and painful deaths I would not wish on anyone, certainly not a beloved friend or family member.
It's just that I've yet to see any of them actually ask for a fatal dose from the bowl of morphine at their bedside. They could have. They didn't. Many talked of slipping away when the time was right. Retiring to a room and taking some pills as the party went on without them.
Never once did it come to that. It was in those deaths I think I learned a great deal about dignity and life. Those lessons are coming in handy now as I deal with family members who are close to the end of their lives and confronting the various overwhelming emotions, physical limitations and flagging spirits a part of carrying on til death does them part. Obviously, I'm still in touch only with the Survivors ... those who survived the Plague and -- more importantly -- those who survived watching wave after wave of their dear ones die without letting Death conquer their minds or hearts.