@juliank @wagi Yes, they do (for newer versions of Android), but the issue is that the upstream kernel stops supporting kernel versions.
So should Google attempt to support kernel versions for many years all on their own? That's up to them but it's something I would never advise them to do as that's an unwise and thankless task.
The companies that should be doing this are the chip OEMs that provide the hacked-up SoC kernels to the vendors. They are the ones that actually got paid for that kernel and support from the vendor. But they know they too can't even attempt to do that as they refuse to do it today.
So the only real solution is to jump to a newer kernel version. That is something the SoC vendors, and Google can support and do today.
Again, it's just one more package to update, not anything magic or scary about the kernel here.