There is a science called gerontology, which among all other things studies the process and reasons of why people get older, and eventually die. According to it, the process of aging is not an inevitable and inseparable part of the life. There are actual organisms on Earth that NEVER DIE (for instance some bacteria and even one species of the jelly fish!). But as it turns out, the nature has “decided” that for most of living creature the aging is NECESSARY. The fact that dictated this decision is constantly changing environment around us. The nature tries to adjust a species to the changing world and so it “decides” to get rid of the outdated organisms in order to give way to the newcomers. Here, the nature’s decision means evolution, or the natural selection. Individuals die to let their species survive.
But on the everyday level we constantly meet old people, we see some of them die, and we KNOW that it’s normal. We don’t understand why, but we believe that it’s OK to die at the old age because it always has been like this.
At the same time, almost all of us want to live as long as possible. Even longer than it’s possible.
This is the reason that when we see a person, who is 80 more years old, we feel some kind of respect to him or her. We feel there’s something spiritual and respectable about those wrinkles on their faces, the way they sit or talk. Intuitively we feel that they’re more experienced than us, that they know things better. So we often forget what’s behind those people, we don’t think whether they misbehaved in the past or used to break a law, for example.
May be the reason we often idealize old people is that they made it through so many years, while we ourselves don’t know how much more time it is there allocated for us.