Why is only 1 in 20 games a close match?
The MMR system being used is completely non-sense. Win or Lose, my matches are riddled with people that are completely unmatched. Whether too high or too low, it's a guarantee that one team will be completely superior, or atl east a handful of players will be completely superior.
Too many people win games where they are simply matched against a completely inferior team, and think that they are God of LoL. The reality is, the ranked system isn't accurate at all. The same applies to many losses these people will encounter - they have too many players on their own team that simply should not be playing in such a high division.
When you climb the divisions, skill and general understanding of strategy and mechanics plays a large role. But at lower elo, the only thing that matters is how many over-ranked players Riot will put on your team vs the other team. Because 50% of the players in silver and high gold still don't understand simple concepts outside of how to use the abilities on a few champs.