Modal age of death is usually in the 90s. Old is a subjective term. I guess people mean an age associated with frailty. People who die below 76 often die from non frailty associated diseases, and so their lives have been cut short before they got ‘old’.

Of course frailty is also subjective and relative. It’s why everyone seems old compared to their prior self, and yet equally seems young compared to your elders.