I paused at 18:43. I'll see the rest of the video later.
But as I can see they're basically saying that NIP/Fnatic played as a top 1 team in a most consistent period, while SK became a top 1 team an then started getting eliminated prematurely in the tournaments. That's fair. But we have to consider that NIP era has ended, and so does Fnatic era. Of course SK are not as consistent as those 2 teams at their peak, but let's see if I can explain this in the right way to you:
For example: In a race tournament, the winner gets 3 points, the second place gets 2 and the third gets 0. In a period of 3 races, the racer 'A' won the first 2 races and finished third in the last one. So he got 6 points in total. The racer 'B' finished second in the first 2 races, and won the final one. So he gets 7 points. The last racer doesn't matter in this case. So what I'm trying to say, is that the racer 'B' always stayed on the top(2nd-2nd-1st), even though he wasn't the best in performance. While the racer 'A' was dominant for a period of time, but dropped his performance at the end(1st-1st-3rd). SK in this case, is the racer 'B'. Not dominant, but always on the top.
And before you say it isn't fair for the third place to get 0 points, in F1 they use this same system. If a Racer dominates the entire championship but decrease his performance at the end, the guy who didn't won any race, but stayed at the top till the end wins the Championship. Vettel for example on his first title. For the whole championship he wasn't the first place on the ranking a single time, but he were always on the top.