Comparing who has the most to lose on December 1st between the Leafs and Nylander is pretty one-sided.
If Nylander doesn't sign before Dec. 1st then:
He will be almost guaranteed to be paid less, whether it is in either the Swedish Elite League or the KHL (his rights are held by Avangard).
The sports medicine, trainers and coaches that the Leafs have available cannot be matched so it is very likely his development will be stunted.
I doubt that the quality of Hotels and definitely the safety of flights (see Lokomotiv Yaroslavl plane crash) can be matched.
He will be in the same position next year as well.
If he hasn't signed by December 1st the Leafs will definitely miss having him for the rest of the year, he is a great player, but they are currently 9-5 in 14 games without him and would have a huge amount of cap space to load up for the playoffs, they would continue to hold Nylander's rights for 4 more years after this one and would have a fan base solidly behind them because it will have been Nylander's decision to abandon the team for the year by not signing. He will be perceived to be greedy and most fans won't want him back.
It is painfully obvious who has the most to lose and why before December 1st the Leafs will either get a very good return in a trade for Nylander or will get his name on a contract that the Leafs feel is fair.