Why doesn't ranked work off "stats" and where they are consistently average?

Although a ladder system works where you gain lp and climb and pro players are able to get unranked accounts to Diamond+ with enough time, wouldn't a ranked system that judges players based on their stats be more accurate in determining a players level of skill? Let me elaborate this is kind of a mix of 2 different ideas.

If you create a system that judges players based off stats (I don't know what specific ones they would use they would use ones that most accurately represent player skill and i'm not just talking about standard kills deaths assists cs etc) and what level of game they are playing in wouldn't it place a player at their accurate rank faster and force players to focus on self improvement rather than just winning a game?

For instance, playing in ranked queues will collect your "stats" and as you play more games you will get more and more accurately placed where you belong. Whichever "stats" this system collects during your time playing it will compare you "stats" to the other people who are playing the game. If it deems your "stats" in the top 5% you will be diamond and the division is where you fall within that percentage. The system will take into account your stats and the rank of the players you are in a match with. For example if I am being matched in silver games and am racking up poor "stats" in silver rank it may drop me down to bronze where I will play more games and my "stats" will be higher and will be on average compared to the people who are within bronze in the particular division. Once I start getting above average games in bronze and surpass bronze 1 average, it will raise the difficulty of the match and give me better opponents in silver 4 and see if I can handle it. The system would try to place you in a rank where your "stats" are average and not poor or extremely good consistently.

Tl;dr

In simple terms, If I am playing diamond games and have average "stats" I am a diamond players that is in the particular division. But if I am in silver and have average "stats" I am silver player in the particular division. If a diamond smurf plays in bronze matches and maintains way above average "stats" and keeps getting those above average "stats" as the player skill increases once they hit diamond their stats should no longer be way above average and should level off to average when they reach diamond.

Thinking about it, this idea runs off having certain "stats" and what rank you are able to achieve average level in and placing you in a rank where your winrate is 50% by matching you against players that have a higher or lower level of skill than you until you reach that 50% winrate. To be most accurate, there would be "Overall winrate" and "Winrate in diamond" specifically. Your skill level should be where that "average winrate" reaches 50%

This is kind of a mix ideas that could be used together or separately. The "stat" inclusion keeps it to where you can still be a diamond rated player if your perform average and can be in a diamond level game without being murked every game and keeps it where if people constantly feed and you lose but do good for the situation you are in, you won't be demoted.