So you have discovered the solution to eternal life. There would be no breakdown due to processes involved with aging.
1. Population Control.
*With a constant influx of people it is plausable that the planet will fill up extremely fast. People will be able to live forever and have as many kids as they’d like if unsupervised.
~Solved by limiting those who are allowed to have the drug to those who go through the “school system.” Having children outside of the government program would be illegal. Do note that even if someting is illegal the level of punishment differs, and the level would need to be high enough to make having a child looked down upon.
2.Who to tell that you have discovered the treatment.
*Are you going to make the drug available to everyone? How many years is that young twenty year old going to be willing to bag your groceries before they crack? If people don’t age then the won’t leave to open up slots for people to rise in the ranks. People always will want to improve their standing, and that can be hard if the people above them don’t budge.
~Technology to make their jobs obsolete, and a lifestyle that has a higher value on enjoying life and having fun. Certainly the short lifespan of life gives a pressure to get better before your time runs out. Without that pressure to rise people will be more likely to be relaxed, and willing to take their sweet time. Plus! Travel, and trying out new things is an option. How long will it take for you to get bored of your high class position before you get bored and want to try out out something new?
*There’s a power flux concerning having the ability to give people this option. Why not just make an insider’s club, and keep all of the riches to yourself?
~Well. Share it with like minded people who you trust, and work from there. By sharing with a larger group of elites it is possible to boost just how powerful you are because everyone who joins the club is granted entry by you.