Google makes promises they keep. They might kill stuff off, but they arguably are always fair about it. I was a stadia user, they basically let me do a bunch of gaming and get a bunch of gaming hardware for free in the end.
Nest products have also had a very long lifespan, only the very very earliest hardware that uses nest infrastructure has been killed off. That includes the Wi-Fi products which are supported much longer than the routers of many competitors in that space (e.g. Netgear).
Google A) hasn’t had the market pressure and B) up until recently hasn’t had their own chip, which has made them rely upon Qualcomm … which has been a huge issue for all Android carriers.
Now that Google has their own chips, I would’ve be surprised if even the Pixel 6 and 7 get extended lifetimes.
Not to mention, if they make a promise, they can get sued for breaking it… so if this leaves the rumor mills, and they say “7 years minimum”, I would absolutely take them at their word.