State is the heart of each application and there is no quicker way to create buggy, unmanageable applications then by producing inconsistent state. Hence many state management solutions try to restrict the ways in which you can modify state, for example by making state immutable. But this introduces new problems; data needs to be normalized, referential integrity can no longer be guaranteed and it becomes next to impossible to use powerful concepts like prototypes.
At Mendix these restrictions where unacceptable and so MobX was born. MobX makes state management simple again by addressing the root issue: it makes it impossible to produce an inconsistent state. This makes state management simple and scalable again.