Similarly, many users don't have much valuable, unique data on their computers. The most important stuff very often lives completely in the cloud, where it's properly backed up, etc.
Also, the most ubiquitous computing device now is a smartphone. It has all the automatic backup stuff built in, you can put an SD card into it, and it will transparently extend the free space, without hassle. Even on PCs, MS and Apple nudge the users very prominently to use OneDrive and Apple Cloud for backing up their desktops / laptops. But past certain size, it costs money though, hence many people opt out of that. Again, because most people value the lowest price, and just hope for the best; because what could ever happen?
Silent data corruption can still be an issue, but, frankly, malware is a much bigger threat for a typical non-technical user.
Technical people have no trouble setting up all that: mount your disks under LVM, run ZFS on top of it, set up multiple backups, set up their own "magic wormhole" to share files with stranger easily. But they know why they are doing that.
Educating users about IT hygiene is key for improving it, much like educating people about the dangers of not washing hands, or of eating unhealthy stuff, helped improve their health.