Even if we assume the absolutely most charitable version of everything for Marner here, that he really didn't have his mind made up long ago, etc, etc, etc. The smartest, best, and easiest thing for him to do after game 7 would have been to hang out at the cottage until he made his decision, make your decision, drop a message to the fans saying goodbye, go to Vegas to spend a week doing a media round and buying a house, take your ass back to the cottage until September without taking any Toronto media requests or saying a word on social media, and then fly to Vegas with your wife + kid and start your new life. Tell your agent to keep his mouth shut and focus on the future.
What we've seen instead is an extension of the last 9 years. Thin skinned ass bitch couldn't handle people saying mean (but true) things about him and he had to try to win a PR game he's lost badly at for the last 6 years and should have given up ages ago.
It's not the media's fault airing shit that will get attention, that's what they do. Players have left cities before a few times, this is not uncharted waters. Thank the fans, move to your new city, keep it moving.