First of all, I'd just like to say that the tournament isn't over for NA. The second best team in the world (based on MSI results) is still in the tournament and they still have games to play, so lets not write NA off just yet.
There are some great conversations happening on a previous thread and I wanted to share a more detailed analysis of my stance here.
I personally believe that NA struggles because the casual player base of soloque games in NA is not as competitive as the casual players in soloque of other regions. I have no evidence to support this, but I'm willing to wager that a large bulk of NA soloque players are casual players, who maybe play a few times a week and move on to other titles or go out and do other things. After all, there are so many options for the gaming population as a whole in the region, that I just don't think a large number of players take the game as seriously as players in other countries.
Now, what does this have to do with competitive play?
The answer to that question is that if the average NA soloque player isn't very good because they don't spend a lot of time with the game, then our ranked ladder is far and away inferior to the ranked ladder of other regions... meaning that the amount of high quality players is severely lacking and the high quality players we do have ARE NOT high quality compared to other regions.
We've all heard that "NA Challenger is Korean Silver" and what not, and while I think that's an exaggeration, I do think it makes sense. The Korean ladder has far more serious and less casual players, meaning the top of the ladder in that region has a lot more practice against top notch players and require better play to be the best.
There is a reason that imports from other regions doesn't make ours better. They are coming over here and dominating our soloque rank and domination our split, but they are actually getting worse in international play because they no longer practice against top tier players.
If we want to change the skill level in NA, I think the discussion is far more complicated. In order to do so, we need to change the amount of casual LOL gamers to more serious LOL gamers... and that is something that I don't think will ever happen in NA unless the amount of things you can do here gets severely limited.
I think a potential solution is to just bootcamp the entire year in the Korean region on Korean servers... but then could we really call it the NALCS anymore?
I just think the solution to becoming a better region in League of Legends is far more complicated than "Get Good" and "Get on my level." The entire culture needs to change. Not just the game.