Earlier quoted context omitted.
I think the suggestion needs more thought, but I don't necessarily disagree with the idea of making my exit before the dementia really sets in. I've directly cared for two family members who suffered from it (collective 5 years of my life, which I'd like to think gives me a pretty good view of what the disease can actually do to people) and I decided for myself that I'd rather be quietly killed than put my loved ones…
Sorry if I'm missing something but how do you plan to exit on your own terms if it's not allowed, and your only legal tools are DNRs and living wills? It seems like DIY methods could be risky to your family if you're already impacted by the disease, and your own competency is called into question.
At the moment, I have standing orders in place that no heroic measures or treatments should be enacted in the event that I am in a terminal or vegitative state. I've communicated clearly to family members that would be responsible for my decision making that things are not to be prolonged or dragged out for the sake of emotional contrivance.
Without knowing how we will die, it's really quite impossible to plan around it, of course. My comment, more or less, expresses my desire to have more control over my exit in the event that I am put in a position to become a massive burden on those I love; this is something I consider a reasonable and rational request, where the folks that make our laws do not. None of that changes without discussing and sharing our viewpoints on the matter, though, which I suppose was all that I was doing.