guys wdym "luck" ? Single elim is way more hype because no games are less important + Teams have prepared for weeks with new and different strategies it gives a feeling of do-or-die.
While double-elim allow team to do sort of re-adjustment / anti-strat against teams that they may have faced previously in the same tourney which is not the purpose of a tournament, it's like World Cup.
In LoL, they use seeding systems to rank opponents in groups in order to balance out the best competitors before the tournament begins. They don't rely on a random distribution of the orgs and if you get 1st place after groups, you deserve to play a 2nd seed and it goes on. Who really care if your favorite team got crushed in quarter instead of semis, at the end we only look at the winner.