If you use Windows 10 Professional or above, though, you can defer Redstone updates for a maximum of 1 year while still getting the usual bugfixes. I guess that's how long Microsoft wants to keep supporting the not-updated version.
That's OK as far as it goes, and maybe for casual power users (if there is such a thing) it's better than nothing.
However, for small business users who would traditionally also be using the Pro edition of Windows, a one-year delay is marginally more valuable than a chocolate teapot. We're talking about the operating system, the foundation on which the rest of our software base is built, and that software base may cost thousands per machine. The guaranteed support period is missing a zero if it wants to be taken seriously.
So, I don't think Microsoft should be allowed to rely on the kind of argument you make in your first paragraph. If it's going to push everything out as being just the latest version of Windows 10 that everyone must have, then all updates are now "regular Windows updates", and the entire-OS update needs to be as reliable as the essential security update that just replaces a flawed networking library with a bug-fixed version.
If Microsoft can't do that -- and obviously it's an extremely difficult requirement to meet, with ample evidence suggesting that it won't happen -- then maybe the whole mandatory updates strategy isn't such a great idea?