Hmm, seeing as even most desktop OSes out there aren't supported for much longer, i'm not sure whether things are terrible in that regard.

Debian's EOL comes to mind, even Ubuntu LTS isn't supported for much longer, CentOS was supposed to be the more stable option but that didn't work out either.

Though for some reason mobile devices are somewhat crippled in regards to upgrading to new OS releases versus their desktop counterparts: not being update from Android X to Android Y is the real terrible bit here.

Not sure why on earth that should be acceptable or why the drivers should be such an insurmountable problem, wherein using anything but flagship phones with third party ROMs is a total mess (i've personally had everything from the touch screen to radio, to even Wi-Fi stop working).

We are talking about the very crippling of devices. So having n years of updates means that the device will effectively die after that, which is a shame and frankly ridiculous at only 4 years.