The way I see it playing out, if working life extension technology is discovered, it will first be hoarded secretly for many years / possibly generations while the rich + powerful use it to stay in power. It won't be generally accessible until much later, likely after the world is in ruins, if at all. Some people believe that it had been discovered before but lost to the ages. Creepy to think about, but makes sense. If someone could live forever, I would think they'd become a huge target for assassination.
That's a stupid theory. All technologies become available to the general public after a short time. Initially cell phones were expensive, but now even the poor often have iphones. Most medicines including advanced cancer treatments are available to everyone. Especially in countries with socialized healthcare. I see no reason why this would be any different.
