Some discussion of Chrome OS updates.
I own a Chromebook which is now 6+ years old. Last summer, when it hit 5 years, it displayed a notification on the last 2 updates I received saying my Chromebook had reached end of support. I don’t recall whether it said I should buy a new one, but it definitely hasn’t received an update since then.
FWIW, it doesn’t have all the latest features, but it still works well enough for how I use it. That said, I won’t be replacing it with another Chromebook. Mine is so old it predated the now standard keyboard layout, and I can’t stand that keyboard layout.