It does exist for two reasons one being that ELO is a terrible system for LoL, the second is people refusing to look internally to improve but rather blame everyone else for losing.
As long as you try to improve every game you will eventually get out of ELO hell.
To go more indepth into the first point ELO is a system for chess rankings which is a single player game with only your actions affecting the outcome and both sides are equal at the start (slight imbalance to white). LoL is a team game where you can lose even if you personally play perfectly and both teams are not equal, and the terrain isn't equal either, Top has to ward two places in order to be safe from a gank if you are on the top spawn, while the bottom spawn doesn't and bottom lane for bottom spawn needs two wards, however bottom lane is 2 people in the current metagame which means you can evenly distribute the extra cost (75g/3 minutes) over 2 people where as top lane needs to front this out themselves which can be a big deal early on.
So ELO is actually a very poor system for LoL in its current implementation.