'Genuine Decoherence' and Macroscopic Superposition

StevieTNZ

By 'Genuine Decoherence' - I mean collapse of the wave function by a theory and its mathematical equations.

If a micro system encounters a macroscopic apparatus - in collapse theories a definite state appears for both the apparatus and system, but after a tiny time since the system entangled with the apparatus.

For genuine decoherence to occur and be predicted in a future theory, does it need to allow macroscopic superpositions (even if they last for a short time)?

Of course we can keep current QM formalism and have hidden variables to remove the measurement problem.