Google announced the end of support for early Nest Thermostats in a support document earlier this year that largely flew under the radar. As of October 25, first and second generation units released in 2011 and 2012, respectively, will be unpaired and removed from the Google Nest or Google Home app.
Users will no longer be able to control their thermostats remotely via their smartphone, receive notifications, or change settings from a mobile device. End-of-support also disables third-party assistants and other cloud-based features including multi-device Eco mode and Nest Protect connectivity.
This sort of thing is one of the reasons I chose a RainMachine irrigation controller over other options, because they specifically marketed their cloud-independent firmware design. It was vindicated a couple years ago when they started going defunct and grasped for recurring revenue by billing for proxied remote access, but even then they emphasized that everything else would continue to function without their servers.
The onus is on the consumer to reward cloud-independent designs like this. While it has been sad to see RainMachine’s collapse, my device indeed just keeps working. Hopefully it isn’t ultimately killed by firmware or app security vulnerabilities since it’s now thoroughly unmaintained.