Bothering to think about your data from the get-go doesn't mean you need actions and reducers. We don't have a new problem today that didn't exist 10 years ago. iOS apps don't need actions and reducers, so why do web apps need them? When you have a hierarchy of components information should flow down that hierarchy. If each component grabs and updates info directly from the store you are violating the encapsulation of hierarchical components.
When I see folks saying, "Oh just deal with it in the components" I have to assume either A) they're working on an extremely small, self-contained piece (which is fine) or B) they're not bothering to think about their data from the get-go.