The Kapanen deal was good and they probably make it no matter what. But if Marner is making the 9 million per he should be then they probably keep AJ.
But you could also then say that the team chose Brodie over Johnsson. Or keeping Andersen. Or re-signing Muzzin. There is no one move that made the Leafs' salary situation what it is, even if you think Marner is overpaid by roughly half of what Johnsson made.