Wouldn't the point be that
everyone is immortal?
Which present the solution to the whole "everyone dying as you continue to live" thing.
It's safe to assume humans scientific progression will at least attempt a solution to the decaying sun. We'll certainly attempt to leave the planet before things get too bad. Plus, if everyone is immortal the very real thought of preventative measures would be even more established because we'd know that we'd all be around to witness such an event. Humans are very short sighted in their goal setting. Our long term goals typically only satisfy one lifetime or at the most, just a few generations. If we lived forever we'd set very slow and steady but magnificent and colossal goals because we'd be around to see the progress.
Aaaaaand... I read way too much into an IB thread... so here's some boobs to reestablish disorder.
For the weebs