All have sinned each having inherited a sin nature from Adam.
This is true but 'sin nature' is not iniquity. Surely it is the
ability to sin.
It is an interesting question though, unless everyone is being punished for the sins of our distant ancestors (or even our more recent ones) then a sinless life should lead to never dying. Yet this does not happen except in the case of Enoch ( though Genesis is sometimes more poetical than historical, the writer of Hebrews states he didn't die ).
There is no statement in the Bible that says Elijah didn't die (it says he was taken by a whirlwind into the sky - though translators usually say "into heaven" there is no reason to do so).
We don't see even one sinless person walking around celebrating their 3,603rd birthday
It is interesting though that in the two cases mentioned the person disappears, and doesn't wander around the earth. So, if there were other cases we would probably not know about them anyway...