Wilder admitted to turning down truckloads of money to fight Fury instead, so the answer is that it is because Wilder knows he isn't on AJs level.
AJ is more skilled than Wilder and is a power puncher himself. However, Wilder's right landing square on AJ'S jaw would be a disaster for AJ.
Say what you will, he did bring back a lot of interest to the heavyweight division. Selling out stadiums.
That's because he was a manufactured champion. Promoted to absolute perfection by Hearn. Was fed nothing but bums or has beens to build this big knockout reputation which drew the crowds in. Casuals were thinking this guy was the British Mike Tyson, blindsided by the superhero physique lol. He's an OK boxer but that's it. Has no stamina and when he's hit, he stays hit. Look at his record. Won a snooze fest vs Parker. Both guys fought scared of each other. Staggered over the line vs a 41yr old Klitschko. If that fight happens even one year earlier, Joshua is dead. Ruiz smacked him all around the ring and then in the rematch, Joshua ran all night like a chicken. Takam was 36 Povetkin was 39 Pulev was 39 Helenius was 39 Ngannou was a 37yr old Non Boxer Johnson was 35 Sprott was 39 Skelton was 47 lol Breazale and Martin were bums Whyte was inexperienced and was then denied the rematch when he improved a lot. He was never that great anyway. I can't stand Hearn but will admit he played an absolute blinder with Joshua. Made an absolute mint from a very average fighter. Wilder is another bum who lost to every decent fighter he faced. Went life and death with Ortiz who was so old, he had blood pressure issues. No one knows his real age but apparently he's older than what's on record.
Right when they were about to finally do it, Wilder started getting punked by everybody in the top 10. I bet AJ was really kicking himself for not fighting him sooner, would’ve been a nice easy payday and a big name on his record.
I mean, you're not wrong, but the guys voluntary schedule, during his protected era, was considerably better than his perceived rivals.
If they had fought when they both had the belt in 2019, Wilder might have actually pulled off a Andy Ruiz