The risk of kernel exploits isn't the main threat. The complete lack of meaningful sandboxing is a much bigger problem. Most applications need to be able to re

The risk of kernel exploits isn't the main threat. The complete lack of meaningful sandboxing is a much bigger problem. Most applications need to be able to read: - files that the user drops into them or opens through a file picker (which could be OS-controlled, giving access to only the selected file) - their own storage/config directories - read-only system libraries - temp files (again, isolated per app) Just moving everything into this model would already go a long way. We see kernel exploits on phones because you need them to bypass the sandboxing. We don't see them often on computers, because why would attackers bother?