> Once you have code execution as my user
The question is "how"? If you are indeed targeted by state-level attackers, there should be more precautions because you are actively attacked. However, I have stated that "there are low-hanging fruits". I have written up a more extensive reply (https://news.ycombinator.com/item?id=25914440) but the short answer is that you can actually prevent code execution on arbitrary areas on Windows. Upon further research, I now know that there is an analogous equivalent (and maybe competition) for Linux: AppArmor and SELinux. However, I will still see someone replying "there is no solution to this mess" despite having a solution, just unused by developers. It is made harder by other developers who by their choice makes security-conscious developers' lives harder.
> We need capability-based privilege separation on network-connected machines.
Yes, you're correct on that. But abandoning reliable-but-unused security for shiny new thing seems wrong on so many levels.