This league is effed if 20 goal scorers command $8 million.
I don't think too many people are of the opinion that he ought to make $8M right now. Most see him as a lesser player than that, maybe a $6M player. The more interesting question is whether it makes sense for him to commit to a long deal at a far lesser number than $8M. He's not there today. Should he consider it a fair possibility that he's there in three years' time? If he's signing for eight, future potential is relevant.
At the moment, I think he's hoping for a long-term deal that pays for potential, but I doubt that position is going to be tenable for long. A bridge deal where he makes less now for one or more likely two years, banking on improvement, is where I think this ends up. Then maybe he will be able to point to improved production to make a convincing case.
It probably won't be a deal the Leafs can fit under the cap with their other players, mind you, particularly if they plan on improving their defense any time soon. But it was never very likely that the Leafs were going to keep Matthews, Tavares, Marner, Nylander, Rielly, plus significant defense improvements not yet on the team. It's always been probable that eventually, he's traded for defense. Not now, but in time.
That's what this is really all about, and it's Nylander's cross to bear that he's first up. They're going to get the same answer when they ask Matthews and Marner to take a discount for the good of the team. Everybody's going to get paid.