We hit that limit. And yes developers think things will just work - until they don't. When item count and especially app complexity go up, redux becomes cumber

We hit that limit. And yes developers think things will just work - until they don't. When item count and especially app complexity go up, redux becomes cumbersome and you then need to start using action batching, avoid immutability and so on... Second issue is that developers think they know how Redux works, but there are a lot of gotchas. From example on OP - `return state.map(toggleTodo(action));` With large app, there are for sure cases where such arrays are empty - and this thing will get updated and re-rendered even if it's empty. From my experience - in most cases MobX is much better than Redux and it's horizontally scalable - as you can just create new, unrelated stores (something that's total PITA with Redux).