1/28/2022:
I use a Google Pixel 2. I just discovered that security updates are sent out by Google for only three years. The last security update happened in October 2020. I verified this by trying to get an update on my phone. Samsung likewise guarantees updates for only three years, though they have extended the security updates to four years on occasion. So a built-in three-year obsolescence. Very disconcerting. Apple guarantees update for seven years from the date it last sold the phone. Quite a difference. I have always avoided Apple as being the most proprietary of the manufacturers. This support issue does change the calculus.