I wouldn't call disabling the Windows Update service as "setting an option" that it's later forgotten. It's more of a thing an inexperienced user does by mistake while messing around. Windows does things behind you back, like magically restore system files if you manage to delete them, and so on, in an effort to keep running. But of course, some people are like "I deleted those files on purpose, so stay the damn out of my lawn"

But I do get your point, and Windows is indeed lacking an option to fully disable updates, even if it does have an option to defer major updates by up to an year.