Think about it, do you really think all higher order life has this "defect" for no reason? Without aging, the youth would be at an eternal disadvantage in society. The rush to have children would all but disappear without a biological clock. Evolutionarily speaking, a cure for aging is a dead end.
That said, i could easily see it happening, so like I said, I'm terrified.
Also, humans have become so dominant by leapfrogging biological evolution with our technological evolution. This would just be one more example. It would not really be a dead-end unless we're looking at some eugenics angle.
The claim that youth would be at an eternal disadvantage in an ageless world not supported by observations in the current world. If having more time conferred universal advantage then youth today could not compete with those older than them. This is clearly not the case and demonstrated by young entreprenuers every day.
To the extent that the cellular processes active in creative, contemplative, and evaluative thinking are exposed, if it becomes common to unify those processes in the functioning of everyone's consciousness then it is possible it would give rise to a modest time advantage for those who had been thinking longer about the same things.
The more I read the news, the more I appreciate watching The Twighlight Zone :-)
The various problems that you imagine might result from curing ageing can be solved _after_ we solve the problem of hundreds of thousands of people dying every single day.