I'm not expecting it to happen but it's also not as outrageous as you're making it out to be.
If he leaves Toronto he's probably not signing with another Canadian team. Panthers, Stars, Knights, Avs, Rangers and Tampa don't have the cap space. Bruins don't really need him with Pastrnak already at 1RW. He already vetoed a trade to Carolina.
That leaves Chicago, Utah, Buffalo, Detroit and the California teams with a clear need for Marner and the cap space to afford him. I don't think we're #1 on that list but we're probably not last either.