The reasons for this are not technical though. Modern WiFi cards don't have firmware in ROM or flash but in RAM (loaded every time you turn it on) and due to the closed source nature they can't be included with the OS.
"Due to the closed nature of XYZ" is one of the stupidest reasons ever for breaking the computer of your users. They could have an automatic check for incompatible drivers and cancel the kernel upgrade, or even provide a checkbox somewhere in the settings where users can click "I don't care if my drivers are closed source or not" that would automatically also update any closed source drivers. I personally derive some perverse pleasure from learning obscure Linux kernel stuff, but I also 100% understand if some cook or a high school French teacher would throw out Linux forever and go back to Windows or MacOS the first time this happens.
(Also, I just double checked and the drivers in question are licensed under GPLv2 so the licensing is unlikely to be the issue)
The drivers are licensed usually but the firmware blob often is not.
But yeah this depends on the distro. Ubuntu is very liberal with this, it simply has a tickbox to enable non-open parts. Others like Debian are stricter. It's up to them really.
