Please correct me if I'm wrong but I'm assuming that you don't have intimate knowledge of any contracts between McBeth & Innova and are only speculating about the details in them. So allow me to make a few speculations too: Innova does NOT have to do whatever is in McBeth's contract. Contracts are broken ALL the time. I'm not saying that they WILL do this or that it would be a SMART thing to do. But if they wanted to, Innova could break any contract they had with anyone, anytime. Of course they would probably be sued for breach (happens all the time) and then the lawyers would negotiate a settlement (also happens all the time.)
As for McBeth, he's definitely the most valuable pro a disc company could have endorsing their discs. For now. But the fact remains that Innova was #1 by a wide margin way before McBeth came on the scene. And they'll probably be #1 after he moves on. Considering how big their business is, and until I can read his contract, I will speculate that the money & energy Innova spends keeping McBeth and any other pro happy is a relative drop in their bucket of costs.