Mid wins Team wins. I'm disgusted

Just had a game where our bot lane was winning, our jungle was far ahead, and our top was winning. But one person in one lane loses and we lose. Mid laners like Leblanc Ahri Ekko, are impossible to win against when they are fed. And there are plenty more cases. Mid laners have the most roaming potential and they snowball the hardest. It's the only solo carry lane for a reason. It has way too much impact on the game.