Very unlikely that Nylander gets 7, he'll sign for 6-6.6 IMO. And Kucherov just got 9 million for his 100 point season, so unless Marner hits that, he won't be signing for 10, more likely 8-9. Your overestimating your numbers. And even if the Leafs end up paying those guys that much, it means that Matthews is a 90-100 point center, Marner is a 90-100 point winger and obviously you still have a franchise center in Tavares and a potential ppg winger in Nylander. If that's what they become to get those contracts, the Leafs don't have to worry about the rest of their offense, they can fill out of the lineup like they are with the likes of Johnsson, Kapanen, Brown, Gauthier, Bracco, Lindholm, Leivo, Grundstrom...not to mention Kadri obviously. That right there is 13 spots and outside of Kadri, are all dirt cheap. Marleau's deal also expires after next year.
Kapanen-Matthews-Nylander
Hyman-Tavares-Marner
Marleau-Kadri-Johnsson
Leivo-Lindholm/Gauthier-Bracco
On the back end the Leafs have their best prospect in Liljegren who can hopefully replace Gardiner next year. If the Leafs can make that swap, they'll save 6 million right there. Add in Sandin as well and the Leafs back end of the future will be
Rielly-XXX
Dermott-Zaisev
Liljegren-Sandin
They won't get dismantled, as much as you want to hope. And in the case were Nylander has to be moved, they would go from a big 3 of Matthews, Nylander and Marner to Matthews, Tavares, Marner + whatever defensive upgrade they get for Nylander.