I think skill is impossible to quantify

objectively wrong, just because people cope about their own level of skill doesn’t mean you can’t easily make a system that will properly put players where they belong (also, because of needing to juice player retention due to capitalism many ranked systems have a goal of not only putting you in the right skill bracket but also making the experience addicting and frustrating, which helps cause the coping about individual skill). Now, the biggest problem with sbmm is that it struggles to properly rate your ability to be a teamplayer, because people who do best in supportive roles generally shine in an environment where you’re playing with the same people every game compared to random solo queue games where the easiest thing to measure is individual skill, and also the best way to ensure the highest winrate has a solo player throughout most of the player base is to improve your own skills enough to try and drag the team on your back as many games as you can.