I don't know about the other UIs, but on the web, some things impinge on the model you (and Redux) are proposing.
One thing is: you, in the gamedev world, have the luxury of having a frame buffer to write to. You fully control what gets rendered. Unfortunately, React and its cousins all have to deal with the idiosyncracies of the legacy browser environment. You have CSS, which applies and cascades styles to elements and their children in often non-obvious ways, and is a monster to deal with on any given day.
In addition to CSS, you have multiple potential sources of state. Every HTML slider, dropdown, input field, accordion, radio button, checkbox has its own browser-native state. You have to control for that.
On top of all of this, the browser application is usually just a frontend client that has to interact with a backend server, with asynchronous calls that require wait-state and failure-state management.
One thing that's in common with all of the above problems is: they're localized. All of these things I'm describing are specific to the rendering layer and therefore the component layer; they are not related to central state. A central state trying to capture all of these problems will fail, because component state has to be wrangled locally near where the HTML is; CSS also is component-level; and the network states are often very closely related to each component. If we maintain a central "game state", the data complexity just proliferates endlessly for each instance of the component.
So, the default these days is to keep state very close to each component, including network state, and often business logic also gets sucked into the mix. I try to avoid putting business logic in components, but people do it all the time unfortunately. But it does add to the complexity.
In other words, there is -real- complexity here, stemming from the fact that the web was never built to be a distribution+execution layer for rich applications, but evolved to become exactly that. It's not just bad application architecture or bad decisions by React maintainers.
Maybe I'm wrong, since I'm not a game developer and don't see what you're seeing on your side.