Let's say for example that your application is a game of solitaire. Rendering the cards is a view concern. Interpreting UI events as game actions is a view concern. Accepting or rejecting those game actions is business concern. Animating that acceptance or rejection is a view concern. Persisting or restoring your moves or game state to an API is a business concern with some networking glued to the side of it.
That's sort of a trivial example, but the event catalog for your application might look like this:
name: GAME_STATE, payload: A JSON representation of the card stacks
name: PLEASE_MOVE, payload: A representation of an attempted move
name: MOVE_REJECTED, payload: The card that tried to make an illegal move
A move event would result in a new state event or a rejection event. Your rendering components don't need to know how that happens or who controls the state. Your core components don't need to know if this game is being played on a server or a browser. Your move events might come from a swarm of multiple players. An analytics component can listen to the bus and fire off things that it's looking for.
Library-agnostic reusable components is another question, and certainly a good one. There doesn't seem to be a good answer right now. Web Components appears to be intended to solve that problem, but it isn't looking so good in my opinion.
I would probably go with a similar approach to reducers in Redux: a simple function that takes a state object and returns some library-agnostic representation of DOM. Of course there is no standard representation of DOM that I know of, but you could just output a plain JS object representing the DOM tree. There are probably many libraries out there offering a way to represent DOM that could easily to plugged into (with a simple wrapper) whatever new DOM rendering library is hot.
Redux is so small that it's hard to see why you would need to switch away from it if you're keeping the same architecture, but even if you wanted to it ought to be fairly easy, since reducers are pure functions and actions are (or should be) simple JSON-able data.
The actual rendering of state to DOM is done completely separately by registering callbacks that listen for application state changes.
Of course, if you're using some other architecture to manage application state, results may vary.