I am not defending them in any way for this, but there are probably some changes on hardware level that are not allowing firmware update.
So the thing you have never heard of it quite realistic, and not just with hardware wallets. Trezor One came out in 2014, Nano S in 2016. The Samsung S5 came out in 2014. It uses an outdated Android OS, which can be upgraded a bit, but still to an outdated Android version. Some apps nowadays require newer versions of the OS to run (maybe Android 6, 7, 8, etc.), and since the S5 doesn't support it, it has become quite limited and useless for today's standards. So there you have an example of a useless hardware device.
In fact, the Nano S and Trezor One are in a better position than the old smartphone models. Had you just updated the firmware in time, you wouldn't find yourself in a situation where you can't run the new one. It's the user's fault for not finding a bit of time to update the firmware from time to time. A phone allows you to update to a certain version and that's it. It doesn't go any further.