This is total, wishful thinking bullshit unsubstantiated by observable reality. You say that Mitch is desperate to play for a winner and win without a shred of evidence to support it. What there is a lot of evidence for, however, is the argument that Mitch just wants to get paid and be the #1 guy on his team, whether they win or not. He's not giving the Leafs a hometown discount. He never has.
You are trying to wish Marner into re-signing because you can't accept objective reality (which, I suppose, goes with the territory of being a Leafs fan to begin with, but I digress)
You need to accept the reality that he's gone and, while you're getting there, accept the additional reality that he doesn't give a fuck about winning or losing so long as he gets paid like the top dog and is recognized as the top dog (something he will never have so long as Matthews is a Leaf and draws breath)