Adding on to this, it’s really just simple probability. Each team is composed of 6 rolls. The outcome of a roll can be a thrower, troll, leaver, bad player, average player, good player, smurf, etc.
If you are always a good player (or smurf), you ensure that one roll for your team is always at least good. Now you get paired with 5 other rolls.
The enemy has 6 rolls. So we’re comparing
A = Good + 5Rolls
B = 6Rolls
Sometimes A > B, sometimes A < B, sometimes A = B. It all depends on who gets picked from the player pool.
Over time, every roll converges toward average player (highest probability). So over time, the teams become
A = Good + 5Average
B = 6Average
And, of course, A > B here.
The odds are in your favor if you’re good. It will take time, for some people multiple seasons per rank, but you’ll climb as long as you stay good. If you’re average, then you’re going to stay where you are. If you’re bad, then you’ll drop until you’re average. It does take time, though. You can’t just play 5 games and win them all and go “I don’t belong here”, because you could lose 5 in a row next.
Take me for example. For a long time I was a good player. I ensured that my team always had at least one good roll, and so as I grinded out games, I gradually gained SR. In order to keep my status of good as my SR climbed, I had to do vod reviews, solo and with a higher ranked player, and mechanics drills and watch higher tier gameplay.
Now, I don’t do any of that, so I’ve lost my status as a good player. I am average. I will maintain my rank until I practice to be good again or I fail to keep up and become bad. I may fluctuate a couple hundred SR because sometimes I get a lot of unfavorable rolls in a row, but over time it averages out.