There's something that keeps bothering me since I've watched Tomorrowland. When Frank Walker
arrives in Tomorrowland with Cassie Newton, David Nix says to him something like "Age goes well on you" (sorry I'm French and I didn't get the exact phrase), and Frank replies "You should try"
Since Nix didn't age since 1964's World Fair, I first assumed that he is a robot (an audio-animaronic).
But this can't be, as he "has ideas" (robots can't have ideas, or at least that's what we are told until the end of the movie), he feels pain, and death seems to bother him (when the Monitor falls, he don't look like he's thinking "Nevermind, I'm a robot, I can't die!")
So I assumed that as long as you stay in Tomorrowland, you're immortal. But this doesn't seem to be true either, as Frank arrives as a kid, and in the scene where he is put to exile, that's not a kid that we see leaving the place, therefore, Frank aged in Tomorrowland. Moreover, if you don't age in Tomorrowland, everyone that was there in the first place (Eiffel, Tesla, Edison, and everyone else, not just famous inventors) should still be there. Although they might hide during the entire movie, why not, but that's not my point.
So we know that Nix is not a robot (therefore I assume he's human), but he doesn't age, but Tomorrowland isn't the reason why.
So what makes him "immortal" (or so special)? He is obviously not an optmist, he can't fix things, so why isn't he aging? Does being in Tomorrowland still have effect on the way you age? Is he another kind of robot or something?