The whole concept of game balance is basically impossible

Enough Champions are allowed to be OP for sufficient periods of time that players can end up well above their skill level in ranked by playing those Champions.

Then, when the Champions are fixed/nerfed, those players can hop onto super popular picks that are really strong, and maintain a 49-50% win rate on them DESPITE being over-ranked. So these players can maintain a ranking they're not really good enough for while simultaneously helping bring down the win rate for their OP champion picks to make people think the champion is balanced near a 50% win rate. In reality, balancing on win rates is absolutely worthless.

Let's hypothetically say Darius is busted OP (he auto wins Lane against any melee opponent, and even if he gets camped he can do alright and wins game because his team gets to 4v3 Lane while he gets camped). So any player could jump on Darius, use him to climb up a division higher than they belong by maintaining a 60% win rate on him, then continue playing in that division with a 49-50% win rate (because the amount Darius is OP by is netted against the amount the player is worse than others at that rank). So then Darius ends up with a 50% win rate and people think he's balanced, even though he's busted and just has a reasonable win rate because everyone that plays him is basically self-boosted.

Now, I don't mean this to hate on Darius specifically (he's just being used as an example, although honestly he's a potential culprit). Any champion could be Darius in this example. The point is, every champion no matter how OP will drop to a 50% win rate given enough time for abusers of the champion to get over-ranked. So win rates are absolutely worthless when Champions are allowed to remain out of check for months at a time.

Then we start to look at ban rates and play rates. These are much better metrics of how OP a champion may be, but they're still problematic. What if I ban a champion because it counters who I want to play? Or because the champion can snowball before I can control it even if it's balanced I don't want to trust my teammates? Or because I'm afraid a teammate will pick it? There's too much subjectivity on why people pick/ban things that you'll never make a clear argument.

Again, let's use Darius as an example. You may immediately assume he's OP due to a high pick and ban rate. However, one could argue that Darius gets picked a lot because he has a dedicated base of fans based on his playstyle and character. He only gets banned alot because of that same popularity (better chances to win if you can someone's main). Further, back to win rates, these players may be really good on Darius and win over 50% of their games on him deservedly, while not ranking up due to also playing other Champions they're not as good at when he's banned.

Look at that: I've just justified that a champion can be balanced with high pick/ban/win rates, while simultaneously arguing the same champion could be OP with a low win rate. The simple fact is, based on statistics alone (and not opinions) we have no idea whether Darius (or anyone else) is OP, weak, or balanced.

So, outside of pro play and the top echelon of Challenger, balance is basically impossible. At those levels you can probably assume people always play to win and for nothing else - so their picks/bans are probably OP. However what's OP in coordinated or top-tier play doesn't translate to 99.99% of the playerbase -so here we are with balance problems.

So honestly, why isn't balance more subjective? Why aren't the masses of voices complaining about certain Champions being overbearing listened to at all? Your statistics mean NOTHING in this environment.