once you get over, say $1K, those differences are pretty well moot. I think Peng compared several Denon and Marantz and found no significant changes between them outside of the Amp stages. *shrugs
So no, the difference between the SR 8012, SR 7012 and SR 6012 for example is going to be next to nothing beyond amp power and some extra features that may get added to the flagship. Same with Separates.
Sound Quality, exactly as has been said, comes from the individual loudspeaker drivers, the quality of the Crossover, the design and build of the cabinet, and how that as a whole system then interacts acoustically in your room.
No tricks. No marketing. No fancy Cables or Interconnects. No Jade Risers.