We would have to impose an age-based euthanasia program that any number of sci-fi movies (Logan’s Run) have touched on. What’s more though, I feel that it would be a class separator as most-likely the age reversal drugs/treatments would only be affordable to the rich...which would diminish the population issue somewhat but would in turn cause even more social strife. Overall, unless we are out there populating other planets and do not have limited space and resources such as we have on Earth - this guy is excited about it because it’s his field of study and as a scientist his sole desire is to solve the puzzle he is focused on...but in the long run I agree, it’s a very BAD idea.
I have to admit, the class distinction issue would be my preeminent concern with this as well, still though, I'd imagine it's worth the risk considering the possible benefit anyone could gain from it. Anyway, inevitably, the price would go down as time goes on, as the product would be of such common interest that demand would be 'through the roof', so to speak. So unless some kind of price fixing went on, (which is I'll admit definitely possible) companies that didn't try to produce these products more cheaply, and in greater quantities, would be severely out-competed.
I also understand the objection about overpopulation, and I'll agree that a dramatic increase in life expectancy would cause some pretty interesting changes in our social situation, but as they say, change is inevitable, growth (progress) is optional. I am of the persuasion that curing cancer would also decrease mortality rates, and contribute to overpopulation, but that we should do it anyway. Providing drinkable water and adequate food to individuals in third world countries who need it, might contribute to overpopulation as well, but I think we should do it anyway. It's easy to turn one's back in indifference so to live comfortably in (relative) affluence, but I'd say that's not the way to go. Similarly, aging is one cause of death among many, ending it won't make people immortal, but it eliminates one more killer, and a big one, one that disfigures people's faces, and robs them of their precious memories right before it steals them away from those they love. Though I know overpopulation is a potential bombshell, and I understand the fear there, still I think it's solvable as well, and I think we should try to achieve that and everything else. Currently though, I'd think the actual allocation of resources and living space is more pertinent, and who knows, for indefinite life extension, the solution could be as simple as government regulation requiring a 'no more reproduction until further notice' opt in for access. (Even though I say this as a Libertarian) I'd imagine people would be willing to wait patiently if they knew they would be young and sexy for several hundred years to come.
To delve into overpopulation a little more, my personal favored idea is
the Ark. (Somehow reminiscent of Sim City 2000) When we're able to populate oceans, there's a lot more space to go around. I think economic viability is the main thing. As much as capitalism sucks, you've gotta admit that it can come up with some pretty interesting and creative solutions if properly incentivized. You can imagine cruising through the tropics in one of those perfectly eco friendly bubbles.
We'll probably always have something to worry about, but solving the problems currently before us, and getting new ones is how we've always done it, and as many theoretical solutions or problems that we could come up with, I think we should always strive for the greatest possible outcome, but that's just how I see things, and I know this discussion has many sides to it.