No-one has factored in how quality of life can deteriorate with age.
I'm 76, there is no history of dementia or other brain problems in my family. I am fit and able to garden, cycle and walk energetically.
However, last year I had a brain scan and the consultant said he found evidence of brain degeneration which was typical in older people. It is certainly not bad enough to stop me driving for example but now that I am aware of this creeping on, there is a concern not just of dying, but of what later years will bring. I want to write another book. It will require a lot of research and work. Will I be able to finish this?
So, my suggestion is, if you can retire from a financial point of view, even before 65 (or whatever) DO IT.
You owe it to yourself and your loved ones to make the most of those golden years while you can. It isn't just dying that may be the future problem.
So now I fill my days with an enjoyable and deliberate mix of brain activity (research, writing, playing a musical instrument) and physical exertion for at least an hour a day, not to mention a full life with my family.