I'm n00b so prob i shouldn't speak up nevertheless I have an honest conjecture:
If you're supp or tank - yes - elo hell may apply - and that's because supps, tanks are totally dependant on their teams - can do nothing alone - so even if they're good, the team may be unable to benefit from them, so the statistical chance of winning any single match may indeed default to 50%.
But if your champ has some actual killing potential - sorry, nope. When you have a team of n00bs - and you face a team of n00bs - then the n00bishess of your team and the n00bishness of enemy team counters each other - so unless you are yourself a n00b, you should be perfectly well able SHRED through the enemy team. If you cannot, then you're at your appropriate league.
(Ah, and no, I'm not trying to explain myself. I'm done with Ali, now I'm sucking with and n00bing up Annie ;P)
Does what I wrote above make any sense?