I’d say Sonos over wifi in my house has < 99% uptime reliability. At first, it was because I was using 40mhz channels in the 2.4ghz bands, which meant interference city! As soon as I bumped down to 20mhz channels, things got a lot better.
Still, though, at least one of my sonos devices drops out of the network at least once a month. These devices seem also not to be very good at noticing and re-establishing the group. Usually the solution is to power cycle the device.
All this leading to a thought I had today for a very silly solution: I can uses the SoCo python library on my automation server to find all the local devices. I could do this once in a while to make sure all the Sonos devices are up and running. Should one drop out, I could wire each Sonos to a z-wave switch, and automatically turn the switch off and turn it back on to bring it back.
I believe in the enterprise they call this self-healing.