Notwithstanding the player movements, which could put them on par with Australia (or worse in no-deal) isn't the blindingly obvious impact the economic impact?
We know that RFL fans are not the ABC demographics that attract the high spending sponsors. The average fan is of a more working-class background, with the loss of income / increased costs many won't be at games. Sponsors will not want to put as much money into the game, the grassroots already strapped for cash will have even less money.
As for no deal, that's the French games rather disrupted pretty quickly with delays at all ports, assuming flights work then reduced impacts and the Canada ones too as the air agreements between the EU would be dead and need to be recreated. I would think the sport wouldn't be on many people's mind in that scenario.