I've got to think this career move makes sense if he intends to continue leveraging his newfound star-power and momentum. He's got a great audience that's gonna keep tabs on him, so perhaps he wants to take on new challenges while the iron is still hot.
Wow! I can't imagine how anyone could ever go to space, come back, and then voluntarily forfeit their ability to visit space again in the future. Chris Hadfield, I'm sad knowing that you won't be back up there any time soon making more youtube videos.
The "Riding Rockets" book by shuttle astronaut Mike Mullane goes into this a bit. It's very hard on the families. Rocket launches aren't that safe. And the best time to retire is right after you get back, because that's the furthest time from your next flight. The longer you wait, the more you get caught up in the next one and just want to make it through that one.
He's been in space three times already and it was pretty clear that he was not going back due to his age; otherwise, I am sure he would not have retired.
