but by the ones where you carry your team of retards to victory.
It is painfully evident that you have not found yourself below the 1200-mark. I shall explain why:
To be clear, carrying isn't going 20/0/5 (or whatever silly score), but is instead anything that makes the difference in making your team win:
destroying the enemy team 1v5
This is all well and good, but I recently went 26/3/15 with Annie. I could literally defeat 4 of the opponents champions in a fair fight, since none of them bought magic resist. However, one player on my team had left the game, and the others did not push out (and when they did, were destroyed by the enemy). Annie cannot kill the nexus by herself (and I sincerely doubt Morde would have been able to either, and as much as can be said about him he is one of the best champions at destroying many champions at once).
Add to this that if you are required to carry THIS HARD - that is, 1v5 the enemy - you will have to be placed on a rating far lower than your intended one. You cannot 1v5 a team of opponents with the same skill-level as you.
Putting down wards that create an important opportunity for your team
This is the number 1 reason I prosecute you with a complete lack of understanding of 1200- rating games. I ALWAYS ward, and I ward A LOT. Warding is crucial of course, and it is twice as good in a rating where no one buys oracle's or wards themselves. That is, if players watch the mini-map. See, at 1200-, most players are completely incapable of this. People die as much to ganks and random encounters in the jungle in games where you ward as in games where you don't.
Assasinating the primary damage dealer on the enemy team
*groan*
All the things you explain are what make me want to play solo-queue. And the more you can count on your team-mates not being flailing retards the more these things really MAKE the difference. But I can fulfill all of these to perfection and I will STILL lose a crapton of games to players who do none of them. I can also do none of them and STILL win games over players who do all of them to perfection.
The reason is that the level of retardation found on 1200- is so huge every single game is a gigantic coin-toss. It doesn't help to ward or assassinate the enemy carry, or securing dragon, or whatever else there might be of delicious goals, if your teams are asshats that plays directly detrimental to their own chance at winning. Neither does it matter if the enemy is doing this; you will win whether you ward or not.
I really wish there was a replay function in this fucking game so I could upload some replays to prove my points.
Anyway, to the second part of the argument, the high ELO one:
At high ELO, I don't really care about single player skills as much as I care about the overall game. Tournament games are far more interesting to watch than 2500-ELO solo queue games. Playing solo-queue at 1500+ (I've borrowed a mate's account to see the difference between the ELO I'm at, and I did quite well actually), is far less interesting than playing Arranged 5v5. Almost every single Arranged 5v5 I've played has been extremely intense. There are so many more layers to it. It's not enough anymore to focus on your own game, you have to work with the team, and as you play more and more together you start being able to foresee your friends' moves and how they will react to different situations.
It is really the most intense to watch and play games in Arranged 5v5.