I also think that by allowing people access to resources to die with dignity you are not only protecting the patient but also the loved ones. Taking one's life is not only difficult (usually - I did not know this) but it can be painful and messy. It can also be traumatic for the person who finds the body - no matter if they are a professional or a loved one (I can't remember the exact statistic but over 85 percent of people who attempt to take their own life via pill overconsumption fail because they don't take enough or their body rejects it or other reasons and then you are left with a painful mess to deal with).
Someone asked a question about markers for when you would have this happen - my husband has clearly indicated that as soon as his mind goes he wants out. That's his line in the sand. He saw my Dad with his relatively moderate dementia and could not handle that at all. We haven't talked about pain level though. I, on the other hand, would base it more on happiness - if I was living happily with dementia that would be ok. For me, pain is also a huge factor - living in pain is a big worry for me - I already have daily pain but if that pain reached migraine-level and was bound to continue like that for the majority of the rest of my life then I would like to bow out gracefully.
I loved your analogy of the fruit and pie Pinga especially after you added the clarification. I would extend it to say that a discussion of how it is unfair that fruit comes on a tree also does not help the people who can't reach the fruit to get fruit or get the fruit to make their own pie should they choose. The idea is to help them get the fruit while we also work on developing fruit that is easier to reach - because that is what we have to work with now. Otherwise advocacy is even more exhausting.