What good would that do? Everybody thinks they're a pro. They'd just turn it on the instant they heard of it.
"Do not turn off your computer, 5, 4.."
People don't need to understand tools and systems to use them. Hell, they'll use things for millennia without knowing how they work (quite literally).
The kind of people that would leave settings like this at the default generally don't read tips n' tricks guides to tweaking windows. They simply don't care about that sort of thing. Of course _some_ do, as you would no doubt reply, but again it comes down to numbers-- that volume doesn't justify locking it down.
They aren't clueful users so they could be socially engineered to turn off updates, but once you get to that point why wouldn't you just get them to run a RAT as administrator? That is the end goal, after all. And once you own their system you can turn off updates yourself.
Lastly, we're talking about a switch in the GUI here-- it is already possible to completely disable telemetry and automatic updates on Windows 10. You just need to hack through the registry and group policy or use a third party tool to do it. Anyone who takes control of your computer can do it remotely.
All the children aren't above average. Your average computer user -- even those who are otherwise intelligent and capable of handling Shit The World Throws Them -- isn't particularly tech savvy.
It's like anti-terrorism defenses. The terrorist has to get lucky once. The defender has to be lucky always. Microsoft here are the defender, and they're trying to keep idiots from fucking up their systems. No slander intended, it's just reality.
Disabling safety systems (which is what we're talking about) is simply one of many ways to make larger-scale compromises of the system far more easy to do.
I'm not saying that it's impossible for Microsoft to offer this, or that they shouldn't. And I'd be hugely frustrated myself if I had to deal with this stuff (I don't run Windows, and won't. Hell these days I barely use computers if I can possibly help it, other than my own. And I hate those increasingly as well.)
But dealing with the public at billion-plus user scale is hard.
I play videogames, so I'm forced to use Win10. But if I wasn't, I would have switched to OSX over this.