I was alive and working in the dark ages where the majority of the world did not patch their OS, and we should not be clamoring to go back just because occassionally the the light hurts our eyes.

I'm much happier in a world where only those that put in the effort to research how to block updates and then go through the steps can do so. They are much more likely to encounter info on how they should really think about what they are doing, and whether there are alternatives or partial solutions that achieve most their needs without being as extreme.

Please don't ruin the little bit of herd immunity we've built up.

How does that solve the issue described in the comment you're replying to? Are you comfortable leaving potentially critical remote vulnerabilities exposed for a whole month?

And if you need to restore device, you'll be updated no matter what.

While you can argue it might be nice to have the option to keep the older backup, it’s also kind of a handy feature that I can restore to latest OS and not have to spend time installing updates myself, my data conveniently seeded into the latest software.

At any rate, iCloud is not “backup” in the traditional sense, it’s really “cloud sync” for user data. In that context it’s not really surprising that connecting a new device to iCloud and restoring pulls the newer OS version, given you never really backed up the OS data at any point.