They're not going to give him 20 million to step aside. That's a ludicrous number. It would probably be a few million at best, but Wilder would make much more by taking the fight and it's the only opportunity he will have to win the belts back. He's not going to walk away from that for a small cash out. Fury has even stated he wouldn't even pay him 2 million to step aside:
https://www.youtube.com/watch?v=BwjzO8TybsUIt makes sense for Fury to take the fight as well as it will almost certainly be his biggest payday win or lose. If he loses they'll likely fight again with an even bigger payday, but wins he just goes on to the next biggest fight but right now that's the Wilder rematch.
I like Fury's attitude, and depending on your outlook you could agree with him that hes already beaten Wilder twice. Yeah, it was given as a draw, but I for one was not shocked by the result, but knew that Fury had to do something big in that first fight to actually win it. I think its commonly known that home advantage is a thing, as it is humans judging at the end of the day, and bias will, and does creep in.
If Wilder didn't get that huge knockdown on Fury, I had him winning pretty much every single round, and in fact I think after the knockdown he even came out, and dominated for the rest of the match. I personally don't think one 10 round from Wilder would have caught up to the sheer amount of dominance that Fury displayed. Of course, the second fight he came in all guns blazing, and it pulled off.
The worst thing that can happen for boxing fans right now is for Fury to lose his belts, and the Joshua fight isn't as hyped up. Yeah, its still a huge fight, but ideally I would like to see both men entering that ring with their belts, and battle it out for the others. It will add to the atmosphere that this occasion will deserve.
Wilder wont step aside because this is his quickest route to getting back into the bigger fights. If he beats fury, and there is a possibility of that with his dynamite right hand he opens the pathway of more money because Joshua, and him surely have to face off then. I'm a massive Fury fan, and its just going to be a nearly occasion due to the fact in my head he's already proven hes a better fighter twice.