Apple locks old devices out of updates

Dropping support for older platforms happens for a number of reasons, including hardware-level security problems and lack of interest for ongoing maintenance. Linux distributions even drop support for older hardware. Even the Linux kernel itself has dropped support. A decision to not keep supporting a piece of hardware is not the same as preventing updates.

The thing to focus on isn't that Apple halts maintaining its own OSes on older hardware. Rather, we should press hardware makers and regulators on the boot loader locks and other obstacles that prevent end users from installing alternate OSes, especially once hardware makers end OS support for hardware. E.g., older iPads that can't run modern iPadOS but could easily run a lightweight Linux distribution. This applies to more than just Apple, like some Android devices. "Internet of Things" devices are similarly affected -- Belkin halted support for a generation of Wemo smart plugs when a vulnerability came out -- they told consumers to buy new Wemos and provided no alternate path for the older, still functional plugs.