It almost seems like a tautology.
e.g. By definition the 99.9th percentile person cannot live a 99.999th percentile life, if they did they would in fact be that amazing.
e.g. By definition the 99.9th percentile person cannot live a 99.999th percentile life, if they did they would in fact be that amazing.
This seems far too deterministic and I think is contrary to what you're replying to.
It sounds more like a 99.999th percentile person[0] that constantly reaches too far too early, before being prepared, will not have a 99.999th percentile life. A 99th percentile person who, on the other hand, does not constantly fail due to over-reach, can easily end up accomplishing more. (And there are many other things that might hold them back too - they might get hit by a car while crossing the street.)
[0] in whatever measurement of "capability" you have in mind
There’s no practical way to determine that looking forwards in time.
In particular IQ is not associated with better life outcomes after you have "enough", and that "enough" isn't Mensa level.
The former might be a literal genius (in the genuine unironic sense) in one field, say software engineering of astrophysics or banking or diplomacy.
The latter would be a literal genius in all four fields simultaneously.
There's no CPU that can't be wasted by bad code.