I want to start by saying it's not really right to exclude Eichel from this conversation since he is a similar talent to AM.
So lets look at MM and his 21 season career.
- Goals by a player born in the United States (561) Matthews 166 Eichel 139
- Points by an American-born player (1374) Matthews 297 Eichel 348
- Playoff points by an American-born player, career (146) Matthews 19 Eichel 0
- Games played by an American-born forward (1499) Matthews 292 Eichel 364
Now a quick glance tells me the games played, playoff points, Cup win and Silver medal are the toughest targets.
Matthews will smash that goal total, Eichel should pass it also.
I see both getting the point total
If Matthews stays a Leaf I like his shot at the playoff points, Eichel is behind the eight ball here but that can change fast.
I doubt either touches that games played number.
I am very confident both (because they are linked) will get at least a silver and I would wager a couple medals including potentially gold
Obviously the Cups are harder to predict. I want him to win Cups but I'm biased so we'll just say "who knows" for both.
Now hardware is an area both can gain on Modano, he has none. Matthews has a Calder and hopes to win a Richard or two. Both he and Eichel will hope for scoring titles, Hart and Con Smythe trophies but it's possible neither gains any. Matthews goal scoring is a big edge here because the others depend more on what is happening in the league. You pretty much need a major Oiler injury for a shot at a scoring title and then you have to hope MacKinnon is having a bad year. I don't like their chances.
Both should match and exceed him in All star appearences and that type of stuff.
I think when it's all said and done the three career will compare well with Modano owning longevity, Eichel owning assists and Matthews owning goals, for American born players. Both will need prolonged team success internationally and in the post season to truly eclipse Modano.