"The first person to live to [200, 300, 500, 1000] has already been born"

[Excited Penguin]

See, whereas I..if I were immortal today...would just jump out of a plane, or play chicken with a brick wall, or start up a live ammo combat drill with all my immortal buddies for shits and giggles.  Obviously, bury your nose in a book for eternity if that gets your rocks off, but you could bury your nose today, not being immortal, right?  Might it be more prudent to solve those problems first, before we exacerbate them?

Ok, let's lose the term immortality for a second. Think of it more as advancements in medicine that allow you to live longer. Except it's forever. You're still mortal though. I will still be able to shoot you dead, unless we somehow change our bodies with nanotechnology so that we become truly invincible, or we find some other way to preserve our conscience only to then upload it in a body of our choosing, or in a simulated reality or in our old body that's been fixed in the meantime. But that's highly speculative and not exactly as likely as us solving the ageing problem - not even close.

Secondly, I would be having fun too, no question about it. But I think if you truly started to think about the dangers we face as a species, and you had all the time in the world to do that, technically at least, you would want to do something about it too. Anyone and everyone who would want to prevent death by disaster or accident would too.