There is a world of difference between a content update (creators) and a vulnerability update (patch). I should just be able to opt out of creators updates full stop.
Do you understand how software development works?
I mean, yes, in theory you are correct. However, in order to support you with security updates
without giving you the Creators update, Microsoft would effectively be supporting two different OSes. Now add the next "content update" onto that, and it's three OSes. Fast-forward 10 years and you have another Windows XP situation.
The reality is that very few OS vendors will continue to produce security patches for old releases past about a year after their replacement comes out. This isn't a Microsoft-only problem, it simply requires too much manpower to support every special snowflake configuration everyone wants to run.
For example, the only Linux distribution I'm aware of that enables users to hold off on "content updates" within one major release is Red Hat Enterprise Linux. This will cost you
$249, and you
still only get 2 years of security support before you need to get the "content updates" anyway.
So no, when you consider practicality, "content updates" and security updates are not so separate.