I think you are right that big updates on Linux are just as difficult on Windows, but the point is that you shouldn't have to deal with the issue.

1) Yes, all OSes should respect something like the root/home separation and let you just nuke the system. But this is a lot easier in a world where all your apps are just an apt-get away.

2) In comparison to MS, every Linux seems to be a "rolling release". When we use linux we like it that we always have a not-too ancient version of GCC. But when Windows 10 starts upgrading continuously, sinister stuff gets mixed in.

Keeping /home on its own disk is Unix101

My first UNIX was called Xenix....

I don't do that. What's the reasoning behind that?

It doesn't need to be on a separate disk, just a separate partition. The reasoning is that this makes it really easy to change your distro without affecting your data: all your data is (or should be) in /home, with the possible exception of any databases or webservers you're running (which would mean you're running your PC more like a server, so this won't apply to typical desktop users). You can wipe out everything in your root partition but your data is safe and secure. Putting it on a totally separate disk makes it even more foolproof since you can just cut power to that disk and then there's no way for it to be affected by the system upgrade, but that's overkill IMO.