Marner's a better player than Phil was at any point in his career imo, and he'll probably have a similar chip on his shoulder to prove himself once he's outta Toronto. But I think Phil was able to thrive because he went to a place where he was a third wave type of addition as opposed to being the focus of a team's structure. I think Marner's probably gotta find a similar landing spot if he can, which will likely cost him some big money in FA but after a decade wasting away in that shithole organization, he may want to win more than he wants to cash in on a colossal deal for his last big contract.
Either way, I think he's still gettin' a massive contract. Just depends on how massive, and whether he wants a better shot to win or if all he's after is that extra $15M or so over the lifetime of the deal.