I listened to the behind-the-scenes Sonos presentation on the Ace headphones today.  As I understand it, TV Audio Swap only works with HDMI as the connection/source.  

From a technical standpoint, does anyone know know why Swap is that limiting?  For example, my Victrola Carbon Stream plays vinyl through the Arc.  I can connect the Victrola to the Arc via WiFi with the Arc basically acting as its own router.  What is it that prevents the Ace from being capable of playing that audio?