I don't understand the complaints about 50% winrate. At all.

If you are at 50%, that means you are right where you need to be regardless of rank.

If you were better, you'd climb regardless of bad teammates or bad games every now and then because you will almost always be consistently better than your current rank, which out numbers the handful of bad games.

If you were worse, you'd drop because you don't belong there and again the consistently worse performance would outnumber games you got carried.

If it's 50%, it means your average performance is right where you belong regardless of the games where your teammates do good or bad.

If you're stuck at a rank you don't like with 50% winrate, that means you need to improve yourself if you want to climb, not bitch about Riot rigging it against you.

There's a reason people say to duo if you want to climb. It's about getting carried to overcome the average difference. That doesn't mean you belong in whatever rank you get to, and if you don't belong, you will drop anyways until you go back to a 50% winrate or so, so it doesn't even matter.

And for people who have 55-58%+ winrate in Challenger I or such, that just means they are still better than the average for that rank/Challenger I isn't technically high enough of a rank to properly place them. Also that with the fact said Challengers would continuously play against each other.