I know it sounds like a simple thing to fix, but it might be something that is mostly out of Sonos control. In a situation where the Sonos speaker playing music is different than the device where voice command is made, a Sonos amp and echo dot for example, the Sonos speaker doesn’t know when Alexa is done talking. It receives the command to play music and proceeds, unaware of what other audio is playing in the room. Alexa would need to delay sending the command till she’s done talking or send a command to delay playing music till a certain time. Neither of which Sonos could control.
I get that the Sonos One could be a different situation, since the music playing device and Alexa speaking device are the same device, but I suspect it doesn’t work differently. Two separate modules are used for music playback and voice control, with shared control over the speaker….I’m guessing. That certainly would make it easier to have mic-less versions of Sonos products.
And yes, echos handle this fine, so in theory, so should Sonos products. Echos were originally built as voice assistants, and essentially can’t do anything but playback audio through voice control. The Sonos was designed and built long before voice assistants even existed, and it does not make sense for Sonos to redesigned every thing to accommodate this feature...if that’s what it would take to do it. Don’t know, still guessing.
Point being, although it certainly would be a welcome feature, I don’t know that it’s a matter of Sonos not caring enough to fix this issue so much as it could be a rather big squeeze for the juice.