a 61 point 22 year old player in 2018-2019 isnt going to be signing for 8 years, at only 6 mil.
There a few problems.
1. He hasnt maxed out potential. If hes at 61 points now, he should easily reach 70 at his peak
2. 7 mil in 2019 is a lot of money but 7 mil in 2027 will be quite cheap for a 70 point guy (Tavares is 80+ points for 11 mil for comparison, AND he left money on the table to come to Toronto)
3. this 8 year contract eats into his prime years and teams will be willing to pay 8 mil at that point (his free agency years), or more (depending on his play)
7 mil is sensible for both, a bit strenuous for Toronto in the short term.
Marner might be in the 8-9 range. Matthews i "hope" will be only 11 to fit in with Tavares. Those 0.5 to 1 mil type "giveaways" from top guys will be able to pay for a better defence, and they're well aware of that. As is management.