The IIHF has no power over North American hockey. We have our own ice size and rule book, we would just continue on playing our game.
However, cooperation is better. The IIHF, IOC, and TV networks (my idea, the TV networks could foot some of this bill, they profit from the Olympics) should come together and cover the expenses for the NHL to go.
The NHL players want to go.
Yes that is why I say they have no leverage and why they are willing to sanction the World Cup. Better to be on the same train than openly shooting at each other.