I mean it's clearly obvious that it's easier to score when your team has an extra player on the ice, which is why people compare scoring rates 5v5.
Powerplay success is also heavily dependent on the skill players are surrounded by, but more importantly, the scheme the coaches implement. This is probably the most underrated part of powerplay success. Every season teams with dynamic offensive players go through stretches of PP struggles or just an overall bad PP because they are following coaches orders and what they practice.
So in this case, more credit should be given to Edmonton's coaching staff. Full marks for Bouchards' shot, Draisaitl's vision and McDavid's playmaking, but most skilled players will produce with the proper time in space. Credit Edmonton's staff for creating schemes and setups that utilize the talent of their players and provide them with that time and space.
The point being, a successful PP (especially a historically successful PP) is more of a reflection of the coaching staff than the players, but the players get the recognition for their execution. Which is fair, but it doensn't make them supreme beings compared to other skilled players around the league that would find equal success in the same situation