I am thinking that a world without the fear of losing your mind when you get old would be a very, very nice place to live

Oh yes. My mother's parents died in their early 70s, both very frail and suffering the early stages of dementia. My father's parents both cleared 90, in great health until the very end. My mother is in her early 60s and already getting frailer; my dad is the same age and healthier than I am.