Let's get this out of the way first: "the five 9's" is not a requirement for personal computers. That argument therefore is invalid.

But even then, Microsoft is testing "Hot Patching" windows installation so critical updates install without requiring a reboot [1].

When that comes out, I wonder where the goalposts will be?

[1] https://www.windowscentral.com/software-apps/windows-11/micr...