If Wilder invokes the re-match will have to beat Fury and then have to beat Joshua in order to become undisputed and unified heavyweight champion of the world.
If he steps aside by taking $20 or so then allows Fury and Joshua to battle it then fights just once in order to have a chance to unify the belts and become champion again - that makes sense too.
Do you think the promoters will be willing to give Wilder $20 million to step aside, i have no idea about the money they are talking about but it is a really huge amount for not fighting if the amount is around those figures. I bet the Wilder camp does not want to take the immediate rematch but with the ego Wilder is having he would not let that go either. If Wilder takes the money and let Joshua and Fury fight then there is no guarantee that Wilder will be getting the fight again.
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.
Is this fight still going ahead? Just six weeks away, don't see them turning down the $ from a live gate.
Fury said it will be towards the end of the year. Check the youtube vid above.