[cptskippy]

That's an oversimplification because it requires the utility of the device to be maintained over it's operational life. Routinely the utility of the device changes as new features are added or removed during OS upgrades, support for software, and eventually hardware support is dropped entirely. It doesn't matter if the hardware is still functional.

This isn't even necessarily in the vendor's control. For example, Google Chrome just stopped loading TLS encrypted sites on my partner's MacBook this past week and displays a lovely pink banner over every tab saying the OS is no longer supported.

Companies are not held to any standards for support and the amount of support they give varies based on the product. Apple has provided decades of support for some products but considerably less for others because they shared an architecture or platform that was eventually dropped. Google is notorious for just dropped support for products on a whim.

And subscriptions won't fix this problem.