I tell folks to think of the game as dice rolls not coin flips. Dice do a better job of representing a range then coins but are still usable for 100% RNG testing.
For this illustration The team with the highest combined scores wins. We can also represent players skill gaps are what # of sided dice you are. Weak players can be a d6 average would be d10-12. A troll, would be d3.
The power of being consistent can be shown very well here. A lot of league players go all or nothing in their playstyles. Win, win more. Lose snowball the enemy. Full range of Great to terrible games.
If you can play from behind. You change your average role by removing the lower value roles. You don't hit a 1 or a 2. So even thou you as a player cant put up a 20 point performance in the match. the more you cut away from your bottom end the more often your team can win, even if your not the same value as other dice in the match.
D 10 average. 5.
D10 that wont hit 1,2,3. is 7.
D12 6.
A loaded d10 > standard d12.
MMR and Elo systems represent a range. So one way to up your rating is to cut out your bottom end games.
I like that you made this post to help others. I am happy you learned about playing from behind. Getting better at playing from behind was how I made it to gold the first time.
Honestly only an idiot assumes all players on their team are better then the enemy team. Some one is gonna get outclassed, some times its you.
My opinion is your not "letting team carry" Your just not dead fucking weight for your team if your enemies stronger. All it takes at that point is some one on their team to get outclassed and be deadweight.