The pitiful(at the time)Sabres had to make sure that Eichel signed with them long term, and they had the cap space. Overpaid a bit...yeah, but they didn't want to risk losing him after his RFA years.
Leafs are in a different situation team wise, but Marner is almost as much of a must sign player. He is a local kid, beloved by the fans(my 90yo Dad loves him), and every point he scores while Mathews is out and Tavares lags behind just makes his case for him. Nylander might end up being a casualty... I sure as hell would make sure that I had enough to sign Mathews and Marner before NYlander.
Not a big tragedy for TML. Nylander should fetch them something decent in trade, if they have to go that way.