Of course, not expected by a basic user. But if you follow Linux, it is quite well known that the Linux project intentionally does not promise stable internal api in the kernel, they "run a tight ship" where if a program needs to use kernel api, it has to be maintained in the Linux tree. Given this modus operandi of the Linux project, breakage of the old drivers with the new kernel version is expected.

Advice to Linux users: one would best get their the graphics driver and a matching Linux kernel from the same source, either the Linux project, or the OS distribution. Mixing versions downloaded from AMD website with random kernel is supported by nobody and is testing your luck. That is a Windows model and kind of works with Linux only with nvidia drivers for their hardware, although it brings a lot of headaches too.

I agree that the installer should have warned you about the incompatibility at the beginning of the install, not at the end. That sucks.

With graphics, it is usually best to run the newest drivers with Linux, that means the newest kernel possible. Except for the older cards, which are not supported by AMD anymore (which sucks), where one can only use old drivers with appropriate old kernel.