Just throwing this out there. I don't really believe it, but you never know.
What if Richard does really age? It just doesn't seem that way because he is kept in suspension until he is needed.
To help run the others right before they get a new leader and then sticking around for a little bit to help get the new leader ready.
If you look back at all the times we have seen him, it could work.
When the Losties crash John shows up to become the new leader and oust Ben.
Richard was there to help when Ben ousted Whidmore.
In 1977 Richard was there because Whidmore was getting ready to take over for Eloise.
In 1974 Richard was there to make Eloise leader for who ever she was replacing. Some one we haven't met.
Richard was in charge when Locke time jumped and gave the compass to him. Maybe he was waiting to name the new leader.