The key is that Koreans have an unmatched early game, which leads to the ultimate victory condition, snowballing.
The #1 seed from Korea is famed for their tendency to fall behind early and play from a deficit, and the world champions of last year were a similar story. Many group stage games have indicated that Korean teams can and will fall behind early.
Koreans basically invented the 3-man early tower dives, aggressive counter-jungling and deep warding to get ahead early.
I'm pretty sure that was Moscow Five.
I think you simultaneously give too little and too much credit to Korea. They aren't dominant because of some secret trick that the West will someday become privy to, or because they're particularly talented - they're dominant because they work ludicrously hard to become dominant, and they do so against much tougher competition than teams in other regions can. Even if the West can hire coaches and analysts to match Korean's, they're still going to have to deal with the fact that they can only play against Western teams.
I mean, look at the people who aren't going to worlds. We've got teams like Supa Hot Crew, Curse and Dignatas in the west, who would be projected to drop out of virtually any group they were seeded into. Meanwhile, teams like SK Telecom T1 K, Najin Black Sword, the KT Arrows and the Jin Air Stealths - all teams that could challenge on a world stage - are staying at home in Korea. The west is sending six good teams to worlds, because they only have six good teams, and that fact inhibits the growth of the region just as much as the disparity in infrastructure.
(This is a big part of why I'm against Riot's decision to limit movement of players between regions and only host one serious inter-regional competition each year - it deprives the west of the opportunity to learn from or theoretically grow to compete with China/Korea)
However, the sword cuts both ways. The Koreans are playing the same game as everyone else - they aren't using secret information to win these games. They're just playing better. A foreign team at the top of their game and a Korean team playing 'meh' would look pretty damn similar, or potentially even favor the foreign team - case in point, Alliance vs. Shield (both games). When we're taking foreign teams with insane talent, synergy and strategic understanding like EDG or Alliance and putting them against middle of the pack Korean teams, there isn't actually that big a difference.
Whomever wins between EDG and Royal Club will be from a comparatively weaker region, sure, but they'll be the best in their region. There's an argument to be made that Shield isn't even the third best team in Korea - so sure, they're from a stronger region, but they're a lot weaker relative to their region than EDG and Royal Club are to theirs. And if I were to bet money on the outcome of the match, I think I'd put it on the Chinese team.