Should probably add a caveat that none of that applies when there is a duo queue.
Honestly have no idea why duo queue is still in solo queue.
Except duo queue means that MMR is balanced slightly differently. It focuses on the average MMR, with premades adding artificial MMR to their team's side (because the coordination balances out the lower skill).
Duo queue can make it look stranger, but it still ultimately adds up.
All of you are around equal skill. I fail to see what your point is.
Why the fuck is a level 39 doing his placement in a high gold game? Especially when the other team has P2 player.
You mean the level 39 that was gold in S8?