That's a very elaborate way of saying that competitive players should delude themselves to cope with their weak mental game.
> Anything below 80% winrate, means it becomes hard to distinguish the learning signal from the variance of the matching.
Using winrate as a learning signal is your first mistake. You're making a million different decisions per game, and then decide to summarize it with a binary W/L?
If you want proper signal, you need to analyze your games on a more fine-grained level.
> And the loss should be correlated to the way you played.
No, it shouldn't and doesn't. Dealing with variance, and things beyond your control is an essential part of developing a strong mentality. Especially when playing in-person.
> The brain also need some balance between the carrot and the stick otherwise the ego take a hit.
If your ego takes a hit from this, you need to get back to the drawing board instead of praying that the world will change to accommodate your issues.
> you can't get past without spending as much time as your opponent on tactics, or openings, and you never get to experience chess on a more strategic level, or deeper understanding level. This mean that most of the fun get extracted out of chess once you get addicted/interested enough.
I can't speak to the "lack of stategy", but what makes a game fun to compete in is highly subjective.
> soulless addicted grinders
This is the exact kind of language and attitude I would see from players who plateau hard, and looking for external factors to blame.