They intentionally choose to handle errors poorly.
Just like they intentionally choose to handle updates poorly, DON'T YOU WANT TO REBOOT FOR THE FIFTHEENTH FUCKING TIME AND LOSE YOUR SESSION WITH 29 PROGRAMS OPEN ACROSS 8 DESKTOPS WHILE RUNNING A RENDERING PROCESS?
Meanwhile, Linux: why yes, I'll update the kernel in-place without rebooting and keep your 784 day uptime.
It moves the old kernel modules to the right location for the old kernel to still find them after you've upgraded. When you restart the system to use the new kernel, the old kernel module symlinks are cleaned up.
Fair enough, and my bad, I though the original question was about live upgrading the kernel, but looking at the thread again, they were just asking about the system not breaking. Thanks for putting the effort into explaining!