Debian updates its stable release repositories every two years (aside from pure bugfixes and the like, of course) because this is what it takes to have a rock-solid software release-- with a truly negligible amount of issues for the computer-naïve "average user" to be bitten by-- given the resources they have at present and the overall state of upstream software. If people want more frequent updates, coupled with the same overall reliability that Debian has always been known for (far more than many other Linux distributions), they're welcome to contribute.

Plenty of software vendors provide packages that are compatible across releases such as google chrome and mariadb. Checkout Mariadb's releases for Ubuntu: http://mirrors.syringanetworks.net/mariadb//mariadb-10.3.11/...

Just the system packages need to be stable (eg, distro's repos).

Also worth mentioning is snaps and flatpacks (though I'm not personally a fan, they do exist).

Average users hate updates, that's a major reason MS (and others like chrome) have to be so aggressive about forcing them, it's why so many stick with XP and 7. They hate security updates because they're an annoyance that does things they don't understand and they hate app updates that change the UI under their nose.

If you gave them a system and promised nothing major would change for 5 years they'd be thankful.

You can run fully transparent updates in Linux using tools from Canonical, Oracle, etc. I have absolutely no idea how people put up with how badly Windows does updates, and really, XBox is not far behind.

There are distros not based on Debian out there, many of which update their packages more often than every two years