Addressing OP champions with average winrates that remain nerf free

It's clear there's 5-10 champs that are deemed to be OP by the community.

But these aren't nerfed because their win rates aren't high enough

But they're regularly banned.

And regularly picked if not banned.

Has anyone actually considered the high proportion of OP champions clashing in matches is whats actually the cause of the average winrates due to their feast/famine and unpredictable nature?

Here's an example:

I see an Alkali Vs Lux. Before the game starts I'm sure i know Lux gets destroyed if akali is half decent and even then by mid game 1/2 kills is all it takes for her to break the game.

Then I see an Yasuo Vs Zed. It's 50/50. I can't say before the match who will probably win lane but again by mid game whoever gets more fed typically steamrolls everyone

Could the matching of broken champions be creating a false % win ratio? After all, it's not like every champ is OP just a few and they could conceivably cancel each other out. Which still doesn't make their existence in their current forms fair or balanced. Because of the remaining champ pool that suffers