It's like dealing with children in here. Last time.
Even if you want to ignore the fact that Rantanen got $12M, and just look at the "4 months of Rantanen (unsigned) for 4 months of Marner (unsigned)".
By Tre approaching Marner to see if he would waive his NTC so that the trade could be made, Tre made it clear that he valued Rantanen more than he valued Marner, and that he was willing to not have Marner on the team going forward.
If you want to look at Rantanen's new contract separately, then consider that, as a better player (and one Tre indicated he would prefer), the current market value is $12M, which implies that Marner's real market value is somewhat lower.
I don't think I can explain it any more clearly.
My interpretation of the Rantanen situation is:
Carolina expressed an interest in a swap for Rantanen.
Treliving knowing marner is not signing with the Leafs during the season and understanding he may go to July 1st., asked marner if he has any interest in waiving, to go to Carolina.
marner said no.
If marner was open to the idea, my guess is they would have to get serious about an extension for both players.
Carolina wasn't keeping Rantanen because they didn't want to lose him for nothing and he wasn't going to sign with them.
Why would they turn around and take a player with less success in the post season who would walk away.
It was reported Rantanen was interested in about 4 teams, and the Leafs were one of them.
'Cane would have done Knies, +, + 2*1st. rounders, Leafs wouldn't include Knies.
I doubt the Leafs would have done unsigned marner +++ assets for Rantanen.
There is talk / rumour 'Canes are interested in UFA marner in the summer, which would mean they'd be willing to pay him his ask.
I think the deal would have been:
Signed marner
for
Signed Rantanen
Leafs only advantage is the 8 years on a term, but as I've suggested the 8 years may be as important to marner as they were to Matthews.