Critical error that always kills the installed OS after 1-2 monts!

There is a extremly critical error in every ubuntu system since 1 year! Netrunner and kubuntu have also that problem.

The bug is terrible. After 2 kernel upgrade the 3th kernel upgrade kills every upgrade functionality of the system. The users cant make any system updates any more. All the security relevant updates are also not been installed any more.
Every time the system reports that there are updates, then it tries to install those. Fails. Then reports that there are updates… And so on.

This is the bug:

Every normal person that asked me to install him a free software OS called me after 1-2 monts that his system cant do any updates any more.
The reported error is also not understandable for a normal user. It reports, that there were no space left.
A normal user then checks the free disk space and tells me on the phone, that he still have 100GB free. He did not know why it tells him that there is no free space left.
Normal users did not know anything of /boot partitions.

Normal users also of course say yes when you ask them if they want an password to save the data from notebook-thiefs or when loosing the notebook.

The most simple solution were to only keep the most recent and one older kernel. When a third kernel is been installed, it should delete the oldest (3th) kernel then at the next boot or before installing the next updates.

Here already existing command line software for that:

purge-old-kernels script

In the bikeshed ubuntu package, there’s a script called purge-old-kernels, that allows you to retain a certain number of older kernels as well as the latest, rather than purging them all.