Based on Nick Bostrom's fable about aging:

https://nickbostrom.com/fable/dragon.html

A couple of points:

(1) Unlike in the story, in real life aging is a natural process that almost all living creatures go through. It is not something that is externally imposed by a malovolent entity. So I would question the implication that not preventing aging is immoral.

(2) Death allows each new generation to take the lead and shape society according to its values. If aging was eliminated social conflicts might increase between the ideologies of each successive generation.

(3) Younger people could no longer just wait for the boss to retire or die to ascend to senior positions, they would have to overthrow the boss in order to advance in the organization.

(4) Even a low birth rate might lead to overpopulation if people don't die.

Aging and death are not necessarily bad things. There is a natural completion to the process. A sense of closure. Do your time, have your experiences, say good bye. Having the knowledge that we will die and that we will lose our youth makes us appreciate them more and gives us a sense of urgency.

Indeed, it is arguably mostly our primitive instincts that make us fear death and want to stick around in perpetuity. Is there something important that won't happen because any specific person dies?

Now, with all that said, if a cure for aging was really discovered I would be the first one in line!

NOTE 1: If the human life span remained the same, but people were able to be as healthy at age 80 as at age 20 that would be great and would pose very little social problems I think.

NOTE 2: Very interesting look at the mathematics of aging: https://gravityandlevity.wordpress.com/2009/07/08/your-body-...