My last Samsung got updates usually within about a month of Google updates, with quite a long pause at the version update and then nothing after about 18 months (there was extra delay as it was via the network operator, so Samsung had to roll out the Google update and the operator then had to roll out the Samsung update, which at one point just didn't happen for a long time). My current Sony (an Android enterprise recommended model which was originally supposed to get longer term updates) got frequent updates that stopped at just under two years. Lack of patches was a big part of why I upgraded last time, so I'm not surprised at all that they just stop. This is something countries should be pushing them on, it's inherently bad for the environment and for security.
It's something that Apple are a bit better at, if you can put up with them gradually downgrading performance for much the same reason.
Biting the hand that feeds IT
