The above article left it as a survival thing, that if predation is such that all are killed in x amount of time, then an aging gene would be coincidentally selected. But that doesn't help to explain how such a phenomenon could arise across all species with different ages and effects.
Some senescence mutations would be almost as old as life itself and thus very ancient and very general. The kind of factors they talk about in that link start operating as soon as mutation and natural selection do.
It is basically enough that you can get away without living forever if you reproduce a lot. Recall that the optimum strategy--other things being equal, but especially if your personal odds are not good--is to reproduce as much as possible as early as possible and get "compound interest." Be prolific, die young; you still win.
Living absolutely forever wouldn't really hurt, but it's irrelevant. It's never been selected. Living somewhat longer can be selected (recall the birds and turtles) where predation is luxuriously light, but enough reproduction eventually happens to take the pressure of natural selection to ineffective low levels for older individuals.
So there are a lot of things--not just a few--in your genome that tend to make you come unraveled over time. You might think it's important, but in fact it has never mattered. Evolution, as Dawkins likes to point out, is about genes, not individuals.
It seems to me that the theory of evolution would require, from inception, genetic coding which did not provide for self-destruction over time. That suggests two things which should be there to support the theory of evolution:
2) there should be evidence in fossil record of when it emerged for certain species (e.g. arthritic conditions of the bone.)