Fox believes Hansen's decision was selfless and based on putting the team first.
"You get to the end of the World Cup next year, whichever way that goes, and that's a big tournament – it takes a lot out of you. So it's gonna be a heck of a big year.
"And I think what Steve has done is put the team first. They know sort of what he's up to. We expect the players to have their contracts – those who are staying and leaving – sorted before next year.
"So Steve has just done the same thing and given New Zealand rugby plenty of time to sort out the process to find out who succeeds him."
The 46-cap former All Black praised Hansen's abilities as a coach and his genuine character, saying he made everyone else in the team better.
"From the get go he's been really open and honest. He doesn't say much but he's got quick wits about him.
"What I think for the guy is he's hugely about his team and his players. There's a brutal honesty about how that environment operates, but there's compassion at the same time which sounds a little bit of a contradiction but the two can go hand in hand.
"He's got a very very sharp rugby brain, he's got great people skills ... in my view, what he's done is he's empowered the people around him."
With Hansen's plans put to bed, the attention will now turn towards his successor. Ireland's head coach Joe Schmidt has ruled himself out for now, which means Hansen's assistant Ian Foster will be favourite to take the reins.