Fighters want the same purses as the second fight, promoters can't cover it without gate revenue. Just guessing.
Wilder is shook! Fury shouldn't delay getting back in the ring. If Wilder doesn't want it, take a warm-up then fight Joshua next year. Yes. And the longer they wait, the less interest there will be in the fight.
Personally, I wouldn't mind seeing a third fight but with interest appearing to have waned significantly in recent months, the money probably isn't there and therefore neither is the incentive to get the fight made IME. Not sure how much either man really wants it either. It's high risk and low reward for Fury and Wilder hasn't expressed much interest recently either.