I think young generations are necessary, but if everyone lives forever, there's hardly space in the world for them.
Maybe it's the fate of humanity and a singularity will just mean that we have reached our limits.
Imagine being able to postpone your career because you and your husband/wife decided to bring someone new to this world. You could still achieve anything you wanted, and not be tied by time in this case.
In this scenario, you get to choose when you die. Would you live a hundred years? Probably. Two hundreds? Most likely. 500? Highly unlikely.
I don't think that the world population might be as big of a problem as we currently think it is going to be. A woman no longer needs to give birth to eight babies to have three of them reach their adultery (as was the case 200 years ago). And, right now, a Western couple is usually able to support one or two children and still pursue their individual career paths. 200 years from now, I cannot realistically say that I don't expect as big of an improvement in human evolution as it happened between 200 years ago and now.
* except for disease, accidents, war, homicide, suicide, and the heat death of the universe
What if they do because they are going to die? Without that limitation, society would be a lot less conservative.