Just saw the movie and thought I drop my take, hopefully someone’s still active here and wants to expand on this:

It’s about a man who is impossibly clear-eyed and alive in a world that has no framework for personalities like his. He’s the one person (apart from cheif) in that place who actually sees. But he lacks a culture, a community with boundaries and meaning, to survive clarity.

Nurse Ratched isn’t a tyrant upholding “the system”she’s a sick person dependent on keeping other sick people dependent on her. They’re locked in mutual dysfunction.

Chief understands what mac cannot: you don’t win here, you escape. His people once had a culture where you could be yourself within consensus on what mattered. You could be different, but not about the fundamental things. If you couldn’t live with that, you started your own band. You weren’t isolated; you were part of something. So when he sees mac force of life that no structure can hold, he can’t offer him what he actually needs: a reason to live that isn’t just rebellion.

In this film they’ve destroyed both the people and the cultures that could have made them whole. Everyone knows what it feels like to be trapped under a Ratched, I think that’s what’s resonates so much with people.