I don’t see why this is hard to understand. Players with “overall” equal skill doesn’t mean they have the exact same skill set, or play at that skill every game. Their play may vary hard from matchups to just missing a skill shot in that particular game. Or even being tilted in real life.
One player might be ridiculously good at csing and gets 10 cs/min. However, the other player that gets 8cs/min might be a better teamfighter and in the end have equal impact to the 10cs/min guy with less gold.
Or players “skill” can vary with matchups. You may be good on Ryze - but the second you play against X champion, like Talon, you have no clue what to do. So your average performance is pretty good, but against Talon you will just chain feed.
Some players also suck at map awareness. A guy can be an amazing Jayce player, but every game is a coin flip because he doesn’t track the jungler. So if the jungle doesn’t gank/camp him - he will decimate your top lane. But he can also get chain ganked and die repeatedly. In one game he might seem like a smurf because the jungler ignored him, and in another he’ll be a feeder. In the end his average rank could be Gold 3.
You could have a super aggressive support who just chain feeds if their ADC is passive. You could have an ADC eat an unlucky hook at now Blitz/Draven are fed so they literally cannot do anything to stop chain feeding.
Not to mention tilt. A lot of times tilt can reduce your map awareness/make you pick dumb shit. Even having a bad day IRL can effect your performance.
**Point is this: even with perfectly evenly matched teams, especially in a game with league that has a billion factors go into your performance. MMR is more important than rank anyways - but “equal skill” doesn’t mean “close games” **
