Yep, good luck with Vulneraibility Wednesdays, if you want to be able to defer WIndows 10 updates, use either WSUS and Enterprise version or Windows 10 Pro and edit Group Policy to choose what to update.

Also: https://support.microsoft.com/en-us/kb/3073930 or
http://winsupersite.com/windows-10/how-hide-specific-updates-windows-10#slide-0-field_images-57901

No idea. Why would you go online with Windows anyway?
Somehow I can understand a Windows gaming partition if you're into the latest shiny dumbed down action rpg / playable QTE movie or new ego shooters, but it just doesn't make any sense for everything else.

Were you online during the blaster epidemic? Blaster could propagate due to unpatched machines. So your unpatched machine had a vulnerability that would cause you to lose your workload, and reformatting wouldn't help, since the machine would still be vulnerable to the same exploit. A patched machine on the other hand would not propagate the worm further, so it could also protected unpatched machines.

Let me give another example. Many of the vulnerabilities lead to elevated privilege access to your machine. So someone could target your machine, gain administrator access to it, then install a keylogger. They sit on the data for a few months, then use it when they have enough. How would you know that you had a keylogger in your system, when it was installed by an authenticated user?

So yes, an updated user is a safer user. Do check what it is you are installing though, if you don't trust the updates, same as with any other software.

In case to avoid misunderstanding, I'll try to elaborate in details.

Let's have one Windows 7 FPP key installed on a PC, and we upgraded it to Windows 10.

You lose the original Windows 7 license if you keep the Windows 10.

If you have recovery partition (OEM license) or Windows 7 FPP key (which we have) and restore it (which is within your right since it's tied to one single machine), you lose the access to Windows 10, but you can reinstall Windows 10 later even after 10 years on that machine.

You can't, however, upgrade to Windows 10 on one machine and use the original Windows 7 FPP key on another machine. Even when it's FPP/Retail.

If you want to move the original Windows 7 key, you must destroy the Windows 10 copy that you obtained through Upgrade Program.

Nowadays most spyware, keyloggers and botnets are out of your way and you won't even know that you are infected, unless you can be arsed to check your network logs all the time. Good luck being in a botnet or getting a nasty rootkit which rewrites firmware on either your hdd or some other component.

Ironically the virus is created by reverse engineered the original Microsoft patch that allowed for execution of the attack

And the same key logger can just use new vulnerabilities for the user who updates diligently.

Surely a updated user is a safer user, but it don't seem to be a significantly safer user.

As for reformatting won't help...... I hope you think I have enough sense, that once I detects a problem in my PC that I must reformat, I would update to the latest version, before turning off auto updates again and uninstalling unwanted updates.
And a user who updates diligently is 100% free from spyware / keyloggers / botnets?

Not using a computer is the safest way.
There are lots of things one can do without; like making music, reading books, playing board games, dancing, sports, etc...
People should try it more often! ;)

The person who updates is SAFER than the person who doesn't update.
As you yourself said, a lot of vulnerabilities which Microsoft doesn't publish get exploited a day or two later the patch is let out, as crackers reverse engineer the patch and see which dll-s and files get changed and where. So unpatched systems make their work MUCH-MUCH easier.

Playstation > Xbox
Piece of shit > GFWL

Hmm.....

Of course a person that updates is safer, but by how much? 1%?

With the huge list of vulnerabilities that continues to grow longer every month, it seems that the user who diligently updates is not much better than one who doesn't

Nah, it's simple and very easy and fast.
Let me tell you my method:

-on the C:\ partition I have W7 installed with kinda regular backup images;
-on the D:\partition I have all the programs that I use but in their portable format.

Reformat, in my case it's just a matter of 5 minutes tops, until I boot from the recovery USB 3.0 stick and restore the whole desired image backup.

fast and easy as pie

It's not going to be something that's easily quantifiable. There are other factors, such as user behaviour.

I can't understand what logic you're trying to follow for the second statement - someone who keeps their machine patched will always be better off than someone who doesn't. Hackers target unpatched vulnerabilities, so someone who patches their vulnerabilities will be in less danger than someone who doesn't. (There is always going to be some danger from undisclosed or 'zero-day' vulnerabilities, ones which are known to hackers but haven't yet been patched by the OS maker.)

But you still lose all the data (save games, ...) since the last backup. In order to not lose any data one probably should do the backup daily. It's only 5 minutes but probably more than once.

Turning Windows updates on is also not much effort. What is the benefit of not keeping Windows up to date?

There is some benefit from vetting patches before installing them - you can make sure that MS haven't stuffed up and distributed a faulty patch which breaks things.