I always look at the full picture. You're the one attempting to arbitrarily overvalue certain point types over ones that are equally impactful and valuable, and arbitrarily exclude everything other than the least accurate representations of production level.
Actually, despite a big opportunity advantage, Rantanen had less points, less primary points, a lower P/GP, a lower primary P/GP, and a lower rate of production and primary production in every individual game state (including even being a worse goal scorer at 5v5), while also not PKing, and being bad defensively, and he got slightly less. That's much closer to the full picture, and Marner has continued his superior play through their second contracts.
Rantanen isn't really better at any part of the game. He's worse offensively and defensively in every game state. The only things he's better at are producing against an empty net and getting drafted to the team that gets the most PP opportunities in the league.
Nobody said PP goals are worth less. You just want to pretend they're worth more, and ignore the context behind that production.