it is already happening with the guys from Saudi Arabia and the whole thing will continue as they are now building the brand around his son. I call that a privileged life! 
He's so ambitious I realize he wants to keep playing football for the rest of his life. But his physical condition won't be as favorable as when he was younger. I think he'll be happy if An Nassr extend his contract even if it's for a small salary. I think his ambition has trumped money. I've read that if he were to retire he'd want to return to the Portuguese club that made his name.
I think An Nassr is currently benefiting from Ronaldo's branding rather than his game. Ronaldo coming to An Nasr has brought money in other forms to the club. I think Ronaldo is still very profitable for the club, even though in terms of playing he has greatly decreased.
This is what he has now been taking into consideration for quite some time, it is not unknown to Ronaldo that age is after him and he won't be able to play forever. But many of the critics have to admit that he is doing much better than almost anyone else at his age. Ibrahimovic was an exception and there are very few other players who were able to play well, but there has never been a player I think who was still able to perform on that level not only in the Saudi Professional League, but in the national team. He is still scoring against some of the best players in the world and for as long as he is able to do that, he will be part of the national team and also able to play the national team competitions like the upcoming WC.