I've been stewing about this for a while and have not yet found an alternative so this is part rant part dear lazyweb plea.
Sonos recently released the 9.0 version of their software which now requires you to have a Sonos account. I have zero desire to sign up for an account or be be in a situation where my home stereo equipment needs to connect to the Internet just to work so I'm actively looking to replace all the Sonos equipment in my home with something else. At the moment the leading idea is to just sprinkle Bluetooth speakers around the house. I don't see any drawback to this approach. with the exception of the Since you need to use a phone or tablet to control the Sonos system there isn't any real drawback to just using Bluetooth audio streaming directly to a speaker.
Honestly since they never got AirPlay or the Android audio streaming equivalent working (for no clear reason since both have been available on Raspberry Pis for YEARS now), nor did they ever support anything other than optical Dolby Digital on the Play:Bar and Play:Base TV speaker products, and since their controller applications just keep getting worse and worse, I am not sad about leaving them. For me, the only nice thing about their hardware that I have found over the years that is missing from most modern network speakers is the inclusion of Ethernet.
So if anyone out there dear lazyweb has an idea of a replacement that doesn't need the cloud to provide base functionality I'd be interested in hearing about it.