- Once there will be a scientific breakthrough in longevity, everything will happen very fast. The time between the first and the billionth vaccine against ageing probably won't be much longer than one year.
- The breakthrough may be just around the corner (10, 20 30 years...) - many people seem to be putting their money on it.
- Sudden increase in the average lifespan by as little as 10 years would throw most pension funds and state budgets into disarray. Mind you, a 70 years old retiree rejuvenated back to his 60 won't be magically as productive as she was before she retired. She will be unemployed and 10 years behind on everything.
- Any significant lifespan enhancement will mean we have to renegotiate social contract about having kids. Will the vaccine come with strings attached? We can't even control our population explosion today.
- Not just science progresses one funeral at a time.(https://news.ycombinator.com/item?id=30025879). Imagine having no real possibility progressing in your career, once the "best" will fill the ladder. Would you want your judge or police chief to be the same person for 50 years?
PS: That being said, I don't think we can or should hold back and it will be all worth it.