There are many people who are pure Solo Q and still end up going up the ranks quite well, yet others don't.
Can it be luck? Sure. But there's obviously something the successful players are doing right that others aren't.
I mean, I did it in S1. Went from 43 at one point to 57 with a lot of solo queue and some duo/trio. I only played 29 hours in S1, but I always felt I could go higher even with occasional bad games or bad beats.
This season it was more or less the same deal. Was placed at around 49, climbed to near 57 (SR2825?) again with little trouble. And then, in the last three days, I've just got pummeled, no matter how well I do individually.
I am usually an extremely positive, non-toxic player, and I quit after two or three defeats to avoid tilting, but matchmaking is just punishing right now, and it was so tempting to just bitch in chat tonight. I fell like 300+ SR in a couple of days playing almost no solo queue, and now I can't get above 2600. And it doesn't help that the community is
horrible down here. Just mean and angry all the time.