ya ive seen the same but in OOP codebases, where the state is all distributed and incapsulated and it's just impossible to reason about how the entire system works because despite it's separation of responsibilities everything is still intrinsically coupled together. and then you have all sorts of hidden mutations and other shenanigans.

to me the best way to design large systems is sort of like an ecs. you don't separate components by state + behaviour, you separate systems and state.