You are correct in both regards. Centralized amps are not the only way to go, but they do have a place. And yes, Apple, Sonos and to a lesser extent Logitech have made that approach optional. I likely over-stated my point...I meant to state it's a requirement for CI, but not exclusive. To be honest, the perfect solution would be a modular system. Sonos like in flexibility but one that could be ganged together in a rack. Sonos really sucks in racks.