Windows does this too where they just stop supporting older hardware. I find the worst part is that new versions of Windows/MacOS are largely just random bloat that nobody asked for.
Apple is actually pretty nice with how MacOS gets installed. Macs themselves have a recovery thing if you want to reinstall. If I remember correctly it is hardcoded with a version that came out before the device was released, but can automatically detect and verify a newer installed version.
They get ya by tracking every last program you open, being hostile towards user choice, and charging you hundreds of dollars for $50 of storage.