The PHWA is the group that selects that so they are going to be a bit more knowledgeable than typical fans, and with less of the weird TO hate that you see a lot of on these boards. Even so, while I think Matthews will get a bit of credit for playing the tougher position if Laine hits 40 and AM doesn't, I think Laine will get it. While the line mate thing seems obvious to some people others will say, and rightly so, that Laine's incredible shooting is the big driver of his success and that Ehlers and Scheifele are not what makes him what he is.
Being ahead in goals, and leading his club to a playoff berth, I agree he is probably the obvious pick today, but he has to stay that way. Laine had 6 shots against the Devils last night and is due for a breakout. At the absolute minimum Matthews needs to stay ahead in points since he has been spotted 9 games. That is a big enough number voters will start to look hard at ppg.
Also its not beyond the realm of possibility that AM finishes 2nd or even 3rd in rookie points on the Leafs. It doesn't make him a worse player but that would diminish his star a bit. Its going to be close. Exciting times to be a Canadian fan.