Windows installation from Mars

I'm going to disagree. Everday new Windows users are not getting machines ready and setup to install their apps and files on that other partition and drive. Asking most to learn this is a pain. Too many folk today just want to use the machines. They do not want to deal with this.

This is not a failure of the makers or those that deploy Windows. Backups of what you can't lose is part of "Windows" life.

If you want to change how this works, take another look at ChromeOS and Chromebooks. You can send a Chromebook into a grinder and user files are not destroyed even if the user never did a backup.

-> Windows is based on ideas from decades ago. Maybe 3 decades ago? Maybe older.

Computers usually come configured with several partition, to wit:

1. Recovery (not accessible through Windows)
2. Diagnostics (ditto)
3. C: (Windows/apps/user files)

I've told family and friends that I will halp them maintain their computers as long as I can get at them before they are first used. Here is what I do

1. Boot Macrium Reflect from a USB stick and take a complete disk image
2. Boot the new computer & do mandatory setup (user name, etc)
3. Install Macrium Reflect and EaseUS
4. Shrink C: & create D: (using EaseUS)
5. Relocate user files (documents/pictures/vides/etc) to D:
6. Install a few utilities (Speccy,CCleaner,PSTools,etc)
7. Make sure Windows is up to date & anti-virus is installed
8. Create a full image of C: and save to D:\Images

If they want I can help them install some apps, then do a CCLean and take another C: image

Generally I ask them to provide a USB stick of sufficient size to hold the C: image file. Now if they brick their system I can always quickly get them back to a functioning system with an image restore. I stress the importance of backing up their personal files but if they don't take my advice that's just too bad. I typically have to restore a system image on my father-in-law's computer 2-3 times per year. Note that with user files on D, restoring a C image doesn't result in loss of data.

Too many folk today just want to use the machines. They do not want to deal with this.

Too many people think that computers/cell phones/tablets are as easy to use as shown in TV shows where you can always get exactly what you want/need in two clicks and a swipe. Real life isn't like that.

My machines all have an SSD for the system and applications, and a large HD for data. The large HD is partitioned so it has a bootable clone of the SSD and a second partition for data. I re-do the clone every month or so. So given a serious problem with the SSD I can boot from the HD and keep working / fix things.
That's in addition to normal backups (TrueImage for Windows, TimeMachine for Mac), and also keeping really important data in a DropBox folder on the HD to secure a remote live shared backup.
Is that overkill? I think not.
Is the average user capable of setting that up and maintaining it? I think not.

If you have the system backup(s) and the data in a partition of the system HDD, effectively you are only securing yourself from user error. If the drive goes bad or if you get ransomware/virus you still have no solution.
Unless the drive with the backup is offline or in the cloud / network don't consider that you have a backup.
I too have an SSD to boot and an HDD to store data in. For emergencies I've got a bootable USB with windows setup always available.
I should backup to one of my old drives, but I can't seem to find the time/energy.
For my work computer everything is in the cloud, so I don't really care.