Because players aren't stat sheets. Jonathan Toews has never scored 80 points, yet for a stretch people considered him in the discussion as one of the best player's in the league. The impact a player has in his work ethic, his leadership, his camaraderie, his attention to detail, defensive ability all factors into the discussion. The complete player determines how "good" a player is, not solely the number of points he puts up.
In short, it's a philosophical debate; you think Draisaitl is phenomenal because he can have a outlier year shooting at 21% and 31% of his offensive production on the powerplay, all while playing 70% of his time with the best hockey player in the league in McDavid. All while posting a sub-50% Corsi at even strength. Never stepping foot on the ice during a penalty kill. Of course, you don't want this mentioned because it doesn't support the narrative. Meanwhile, Larkin is the heart and soul of his team, playing in every situation, and is the #1 option in every phase. He's better defensively, he's better in the faceoff circle. Larkin is the player the Wings organization and fanbase would prefer to build around, flat out. His complete game, and the fact that he's on pace to score 80 points tells me all I need to know. That's not even mentioning that he makes $2.4mm less over the course of his contract. It's a no-brainer for us.
There's no way to substantiate this, but I'm willing to bet that subtracting Larkin from this team and adding Draisaitl to the Red Wings from the beginning of this year, the Wings would be a significantly worse team than they are right now. Fortunately, the Oilers would probably be worse without Draisaitl, and how they are so bad despite having been gifted an embarrassment of riches over the years will continue to mind blowing.