If the Leafs are only trading Matthews they will likely pursue a lateral-ish hockey trade (i.e., Auston Matthews for Elias Petterson, etc.) However, if the Leafs were to trade Matthews for futures, this would be the first fallen domino that leads to a complete rebuild that must include Marner and Nylander as well, as wasting two years of them would be horrific asset management.
Not if you open up another good window 1 year from now. Marner and Nylander are still improving, if you start just surrounding them with talent, it might not even take 1 year. And then you have a bunch of entry-level contracts to keep opening some cap flexibility to add (they have to, in order to transition out of the Tavares situation)
My proposal is lateral enough, it gets both future and PLD as a "good enough" replacement for Matthews. Getting Petterson would get you far fewer assets and cap flexibility for little added benefits.
<== 2x core over 11m, 2x8 million players, but you are up 2 top 6 players on entry level
Tavares - PLD - Willy
Knies - Cooley - Marner
Leonard - X - X
Is vastly superior to this:
Tavares - Pettersson - Willy
Knies - X - Marner
You can't make a lateral move for Matthews, because the problem is the cap, not Matthews the player himself. There is no point in trading Matthews without creating cap flexibility, and entry-level contracts that can play in the top 6 are the solution (rare, so you need to be intentional about it)
In 1994, the Nordiques traded Mats Sundin from their core to the Leafs, they were back in contention in 1995, and won the cup a year after. They did this by keeping Sakic, shifting Sundin into Forsberg (entry level). They were hyper-salary limited, that's why they moved to Colorado. It's a similar situation.