Quoting: ZachArmel
I don't think he's the best player in the league. Is he a top 5 winger? For sure. Fiala has 8 goals and 31 points in 35 (18 goal 72 point pace) Mitch has 14 goals 39 points in 36 (32 goal 88 point pace). Marner plays more minutes on the PK (81 to 2) and is a Selke finalist. Fiala is older then Marner and has never surpassed 85 points, Mitch has passed 90 3 times and is close to doing it again this year despite a terrible start. I promise you the Kings don't think twice about this trade
I think you aren't thinking about value and just focused on points and goals. For instance, Trevor Moore is set to put up more goals this season than Marner, does it mean he is a better player than Marner, no. But does Moore have a better contract than Marner, absolutely. Marner has the 9th most expensive contract in the league, but is the third best player on your team.
For instance, using your example:
Fiala is being paid $7.875M and is on pace for 72 points, that is 9.14 points per million paid.
Marner is being paid $10.903M and is on pace for 88 points, that is 8.07 points per million paid
LA is focused on value-based contracts and a balanced team, next season will be all about getting a great goaltender and reupping Roy or replacing him with a similar shutdown. After that there is not too much money left, so your trade above doesnt work. Because they not only would need to do all this, but replace Mikey Anderson who is on a very team friendly contract for a shutdown #1.