This is usally due to DKMS (dynamic kernel module system). Each time you upgrade your kernel, the nvidia portion needs to be recompiled. If this goes wrong, you end up in a state where you cannot boot.
This is why everyone in the linux world has a very sour taste for nvidia. It's not their fault per-say, but they did opt to go this route versus contributing their drivers to the kernel like everyone else.
In the future or even today with immutable distros, you'll be able to roll back the entire OS the same way you can roll back the kernel to undo any change that breaks the system.
This is why everyone in the linux world has a very sour taste for nvidia. It's not their fault per-say, but they did opt to go this route versus contributing their drivers to the kernel like everyone else.