The proposed state table is hardly more scalable. It's obviously not infinitely scalable but In my proposed way, you only have to specify the cases where a state transition actually occurs.

What you describe feels more like case classes.

one possibility is to use hierarchical-state-machines (HSM), which allow (encourage even ?) the decomposition of state-machine into common behavior for reuse across states.

HSM have been there for a while, being proposed in '84 (!) by David Harel under the name 'statecharts'