Obviously AJ is the money fight for Wilder but surely he has to fight Whyte in Feb. $4 million for an easy fight (he would KO him very easily in my opinion) and then have a stronger bargaining position vs AJ.
Why make 4 mil to face Whyte when you can make 1.5 mil to fight Breazeale, who in my opinion is of equal talent/skill/danger/rank/etc. as Whyte? ...wait. Yeah, why would you do that? Answer: Al Haymon. If Breazeale springs the upset, Haymon still controls the title.
Hearn didn't promise a Joshua fight even if Wilder knocks Whyte out. Wilder would also be giving Hearn control over his career, since there were conditions to the $4 million Whyte fight. Also, Whyte has the WBC Silverbelt so he'll be mandatory soon enough anyway.