Here is how the Oilers might have won the cup last year:
1. If McDavid did even better (I know, ironic considering how great he did). If he had taken over game 7 for example with a couple of goals, they win the cup.
2. If Draisaitl did better. He simply wasn't good and didn't produce in the finals. If he takes over 1 or 2 games, they win.
3. If Bob didn't steal game 1. That realllly set the tone. Oilers deserved to win that game, and if they had, good chance the series goes off in a different way, and maybe Oilers win. So Bob's game 1 performance was instrumental.
4. If Bob didn't bounce back in game 7. He wasn't quite as good in game 7 as he had been in game 1, but still after 3 straight bad losses in games 4, 5 and 6, his game 7 performance with all that pressure was super important.
There - that's the top 4 reasons why Oilers didn't win cup.
If we were to keep listing reasons why they didn't win the cup in order of importance, I'm sure by the time we got to reason 15 or 20, having or not having Kesserling might make the list. But it's not the main reason they didn't win, nor top 5 reason nor even top 10. Having him in the lineup doesn't change Bob's game 1 performance. Nor McDavid's, nor Draisaitls' performance. Nor Bob bouncing back in game 7. Nor many other more important things.