> this would make you ageless until one day you drop dead
No, that's not how this works. How would a person die of an old chronological age if their biological age is, as far as their body is concerned, still 25 years? It's not like there's a time bomb that goes boom after a certain number of years regardless of what you do.
Even without aging, humans aren't immortal. There's a probability of dying from something other than medical issues. Eventually that adds up.
I think the people willing to give up travel at greater-than-walking-speed, sports, hiking, etc in order to live longer is small enough that they won't be a burden. I'm not sure I would really call that "living" myself, but it's their choice.
Totally not reliable, but I once heard an estimate that if aging was cured, the average lifespan would be about 600 years due to various forms of non age related death-- accidents etc.
It’s a group survival thing. It’s helpful to have some reckless members because they discover solutions that others would never explore. In particular, young males have been prewired by evolution to generally be the most reckless members of a group because they are the most expendable. The number of young females determines a group’s reproductive rate and older members tend to have critical skills, knowledge, and wisdom. I speak as a former young male who explored more than his share of possible solutions for the group.
Presumably though even if biological aging were somehow paused at the level of young adulthood, I would think cognitive development would still proceed, so young males would still outgrow that reckless period.
If we can possibly keep the immune and cardiovascular system young indefinitely, thus staving off heart disase and cancers, what is going to break down next? Possibly something within the brain.