goodness, 50 and I only work part time as I care for 2 complex SN teens. At lease one of the them will need lifelong 24/7 care. I couldn't imagine working and caring every waking hours until my 70s. tbh, I don't think I will last that long as I have to completely neglect any self care.
You will find some people who are happy to work that long but I cannot see how this is possible for the majority esp those with physical jobs and caring responsibilities on top. I would also imagine a lot of people have developed all sorts of heath issues which make it generally difficult.