It's only the networked features that are being discontinued. You can still use the Nest as a "dumb" thermostat. Assuming you wanted a smart thermostat, surely a smart thermostat that reverts to being a dumb thermostat after 10-15 years is better than a dumb thermostat.
That’s no excuse to disable functionality on perfectly good devices.
Imagine if a company disabled your freezer after 10 years and told you “hey a refrigerator and freezer that reverts to a refrigerator after 10 years is better than a refrigerator!”
It's funny you should mention that because years ago, I did own a mini-fridge with a freezer section, and after a few years the freezer stopped working. I was still glad to have had it while it lasted.
Sure. I imagine you’d be really annoyed if you found out the reason it stopped working was because the company installed a kill switch on a 10 year timer.