By the time we get these kind of treatments I doubt they will be able to push the overpopulation agenda anymore. The major problem is going to be the demographic shift to a larger population of people being elderly and further, a lack of young people to help look after them. Robots might help to take up some of the slack but unless we can keep people functional into old age it is going to be a big problem. Even if the treatments are initially expensive the costs will come down. They always do.