This is more or less what I think. I'm pretty optimistic here, more than with Nylander, because if the Leafs don't get Marner for something sane (i.e. ~$9.5m on a long-term deal or an inflated but manageable bridge -- $8m?), they can trade him. And, if there are teams willing to sign him for what his side is demanding, the return on Marner would be a LOT higher than what was considered with Nylander.
Instead of a comparably talented and aged defenseman, negotiations start there. Or high-end forward prospect, decent defensive upgrade, and picks, one of which would be a first. That, imo, isn't a bad outcome for the Leafs in the short or longterm.
The difference this time, I think, is that the Leafs have to be serious about holding a line -- whatever it is they calculate it must be (I'd guess $9.5m)--and willing to trade him if that won't work for his side.