I got the feeling Cook would be at Carlton given his response when asked. Something along the lines of "I'm focussing on Geelong in the finals right now".
That sort of answer basically admits he's leaving. If he were staying with Geelong he'd say he's staying, not deflect the question and say I'm focussed here right now.
He's already leaving at the end of the year, regardless of whether he joins Carlton.
Steve Hocking is replacing him.
From the Herald Sun: ' Cook, 65, was set to retire at the end of the season after an illustrious 23-year CEO career at the Cats, including three premierships. He is being replaced by former AFL boss Steve Hocking in the Geelong role but was expected to stay on at GMHBA Stadium in a consultancy role '
So it's about whether he wants to retire, remain at Geelong in a 'consultancy' role, or take up a new challenge (and earn more money) as Carlton's CEO.