But it's not just the players themselves, it's the narrative and the mentality they evoke. The "to his team" aspect has always been a factor in voting, as has making the playoffs, but the narrative surrounding Hall and MacKinnon pushed those two things to the forefront more than I can ever remember in the past and I believe it influenced the rest of the voting. If someone is so focused on those things for the first 2 slots on their ballot, it's going to be odd to abruptly change the narrative for their other picks. And while McDavid finished 5th, it was distantly so. Lots of voters left him off the ballot entirely. As such, players like Giroux and Kopitar wouldn't generally have finished ahead of him, and I don't believe similar equivalents this year (like Marchand, Gaudreau, etc) will finish ahead again. We will see random years where there is a push to something, only to bounce back the next year (like Pronger's win being a push to include defensemen).
I agree he has less of a case on the surface this year, not being the best player and Art Ross winner, but again, voters aren't consistent. I think many will see last year as a negative and try to rectify that. Some might have assumed that the Oilers would be back in it this year when voting last year, so it would only be a one-off year, and don't want to "punish" him twice. I also think with Kucherov the easy winner, they'll be less concerned with "their guy" winning it, and throw him a bone. Also, while he was the best player last year, he actually has a bigger lead over his competition outside of Kucherov this season. The drop to Giroux was only 6 points last year. The closest player to McDavid to make the playoffs this season after Kucherov is 16.
HF is actually an interesting case study for this. Last year there was huge debate on this site about the Hart, and many people went so far as to not put McDavid in their top 7-8 players because the "to his team" aspect became such a huge narrative. People get wrapped up in it and overthink things. This year, I haven't heard much complaint about people putting him top 3 because with Kucherov a worthy winner, people seem content to simply reward the best players.