Why don't heavyweight contenders fight each other?

One of the bonuses of Wlad unifying is that now, all roads go through him. Even if a fighter wants to face Vitali, it's a near certainty that a clause will be in the contract that should they win, Wlad's got the next fight. Every other sanctioning body's contenders are fighting to face against Wlad.

Why's that good? Now, guys can't cherry pick the weakest titlist and simply hang around in that organizations' rankings waiting for their shot, milking easy defenses instead of fighting the best. It also means that if the top contenders want a really good payday, there's no chance of them having a title to boost their own marketability without taking Wlad on. The WBA regular belt Povetkin and Chagaev are fighting for is basically just determining who that mandatory will be. All roads go through Klitschko now, so contenders have to fight each other to get to the front of the line.

This is what the division needed, desperately. The problem has always been, in my eyes, less of a talent issue and more of a "the fights need to be made" issue. If Wlad stays on top for another 3-4 years, the guys who are serious about making waves in the division will have to fight each other for the right to face him, and we'll know who the best contenders are. And that's nothing but positive for boxing fans. Lo and behold, we're already seeing more fights made.

Had Haye won and then retired shortly after, we'd be right back in the same mess that the early 2000's were where promoters were trying to get their piece of the title with no incentive to unify against each other.