The Leafs aren't a hockey team, they are a clothing and merchandise company that occasionally plays hockey. They exist only to sell insanely overpriced tickets and jerseys to blindly loyal fans. That's why they don't change anything despite collapsing every year. They don't need to. Their owners get richer every year, their players sign massive contracts that pay out regardless of how they perform in the playoffs, and they have no shortage of fans wanting to give them money to support them because "this is the year".
The only thing that will actually change things in Toronto is if the fans boycott the team, stop buying jerseys and hoodies, and stop going to games. And we all know that's not going to happen, because as soon as the team drops prices on anything, there will be an inrush of fans who could previously not afford it, and then they'll be right back to where they were again. Management is going to make changes only because they have to, as Marner and Tavares are UFA. If it weren't for that, they would simply put the same Core Fore back on the ice next season, and rotate the bottom six.