It all depends which team have more braindeads on each side. U can be overfed, take all objectives, but if ur whole team is feeding and have no idea what to do, enemy team will just smash u. I used to a lot of games like that. And u too.
Stupid weird-ass matchmaking. U match 5 random players in team and u expect them to be the same skill-lvl'd both in micro and macro and to cooperate like pro team with voice communication. No, it's not possible.
It's all about which team have less players that perform really bad.
It's not solo carry. It's team carry.
My last 3 games are just simple examples. Yeah im writting this topic because of that 3 games, but as I said, I used too games like that. Maaaaaanyyy of them.
I wish there was real soloQ 1v1. Not only on aram, but also on summoners rift, to keep some macro elements.