This is because Quantum Mechanics is not only a theory about the smallest constituents of reality, but about what it means to physically exist and interact. It's a theory about existence and interaction itself.

Existence is nothing more than the unfolding of physical interactions that satisfy the constraints that keep reality self-consistent (i.e, only those interactions that yield the invariant quantities represented by the universal constants in each observer's subjective frame of reference can unfold), so it's no mystery why our classical notions of persistence, determinism, or locality go haywire in the absence of interactions, since the concepts that entail physical presence for us are constructed "on the fly" as interactions unfold according to c, G, and h, no matter how past or distant the events, processes, entities or properties they represent to the observer.

The universal constants are the "checksum" algorithm that keeps reality self-consistent regardless of the observer's frame of reference, ensuring that conservation laws and entanglement are enforced no matter what puzzling relations between events in spacetime the observer may infer.