The pair will fight separate opponents on the same bill at a mega-show in Riyadh on Saturday, with former WBC title holder Wilder taking on Joseph Parker and Joshua, the former WBA, IBF and WBO champion, facing Otto Wallin.
Wilder and Joshua could fight each other next year if both win at the weekend, but while previous negotiations between the two camps reportedly broke down due to financial issues the American said that was not the case.
"Money hasn't been the issue," he told BBC Sport.
"It comes with not having the heart, the will, the courage to step in the ring.
"I don't really just blame it on Joshua. I blame it on his handlers, on his promotion and his management. Because let's face it Joshua is the cash cow of the company.
"Without him, no money is drawn into Matchroom. Not only do I feel Joshua is intimidated of me, but I feel his promoter is as well. That's why the fight hasn't happened."
Joshua meanwhile said that he is focused on the bigger picture.
"I would love to fight for the IBF, and love to fight Deontay Wilder. Either are really good options," Joshua said.
"The championship is worth much more to me, that's special, becoming a three-time champion of the world. Then I'd defend it against Wilder."
