You think he will end his career after several fights? There is still Joseph Parker that might give Fury some troubles. What about fourth fight against Wilder? That will be hilarious and really humiliating if he wins.
Situation with Fury might turn into situation with Canelo, when there are no more new opponent to beat. With Canelo, there are options to change fighting division, with Fury - doubtfully. That the only option for him to fight, Ruiz for example, looser of Usyk/AJ.
I don't know, but he's mentioned possible retirement before. Lets look at it realistically. We're lucky if we get one fight a year from the super-star heavyweights these days. He's 33 now so those three fights are likely to take him to 36-37. Realistically how long does he want to keep fighting? He's arguably still at his peak right now but one loss will change that and is that something he wants to lose? Being undefeated he'll go down as one of the greatest boxers of all time and a loss would severely dent that. I really can't see him doing more than 2 or 3 fights after the Whyte fight. Who else is there? Do the winner of AJ/Usyk, get all the belts, then have one novelty cross-promo fight with Ngannou and call it quits. It's not like he needs the money and seems to live quite humbly for the most part so I don't think he's going to be one of those boxers that is fighting pushing 40 and keeps coming out of retirement for another payday.