They've been the worse team at 5 on 5 in all but 1 game this series. And that 1 game where they were "better" it was basically dead even (50.9% to 49.1%. This isn't about emotion.. I'm reading the same data you are, just without the blue tinted goggles. I agree they are unlucky to not have won 1 game based on how close game 2 and 3 were, but to say the Leafs should be up 2-1 is taking serious creative license with the data at hand. And to assume they are entitled to a cup or a won series despite playing a very pedestrian/mediocre game and haven't really dominated at any single moment (as most cup champs do in many stretches of their playoff runs, making "luck" become less of a factor) is also not the best approach. If every game is gonna be tight enough that your only hope in winning is being the luckier team, then you're probably not gonna win a cup. It just isn't how it works, even mathematically speaking.
Totally agree with your concept of luck being a major factor in this sport, but man you are really taking it too far. It has been my thing for years but I can't get on board with how far you have taken it.